Coleridge's 'Frost at Midnight', written in February 1798, is one of his most celebrated poems. And rightly so, since I can't think of another poem as beautifully evocative of midnight silence: the solitude of the poet by the low-burning fire whilst all the other inhabitants of his house are asleep; his baby asleep in his cot beside him. Coleridge ponders what the future holds for his son, Hartley, and undertakes to raise him right. In the event, Hartley's upbringing wasn't something Coleridge could take a whole lot of credit for; but his heart is in the right place, here. In other words, this is a poem about fatherhood. It is also a poem in which the silence, the 'secret ministry' of the frost outside, and the film of fire over the burning coals—known colloquially as a 'stranger', since it is supposed to portend the arrival of an unexpected visitor—all send Coleridge back in reminiscence to his own childhood, and in particular to his unhappy experiences as a boarder at his London school, Christ's Hospital. That unhappiness is epitomised by the vignette of the boy-Coleridge, told what the fire-film of the 'stranger' on the school fire is supposed to mean, looking up expectantly for his visitor, hoping that it would be somebody from home to take him away. The final section of the poem performs Coleridge's promise to baby Hartley that he will be raised in the countryside, close to the spiritual and healthful influence of Nature, and not sent away to the city as Coleridge himself was. There's something so exquisite in the way the final image of the poem brings us back to the mystic-silent frost and moonlight of the opening lines that it's hard to read without shivers going up the back of the neck.
The Frost performs its secret ministry,It's a poem that has been very often read and studied, usually from a position of frank admiration: it is 'one of his most delightful conversation poems' (Rosemary Ashton); 'perhaps the most beautiful of Coleridge's conversation poems' (Adam Sisman) and so on. Richard Holmes thinks the poem 'one of the most intricately structured of all the Conversation Poems, performing a characteristic 'outward and return' movement through time and space ... This curve of memory and prophesy gives the poem a rich emotional resonance – sadness, poignancy, hope, joy – held in exquisite tension'. What else is there to say? Well, Paul Magnuson notes how Coleridge uses the poem ‘to bless his son’:
Unhelped by any wind. The owlet's cry
Came loud–and hark, again! loud as before.
The inmates of my cottage, all at rest,
Have left me to that solitude, which suits
Abstruser musings: save that at my side
My cradled infant slumbers peacefully.
'Tis calm indeed! so calm, that it disturbs
And vexes meditation with its strange
And extreme silentness. Sea, hill, and wood, 
This populous village! Sea, and hill, and wood,
With all the numberless goings-on of life,
Inaudible as dreams! the thin blue flame
Lies on my low-burnt fire, and quivers not;
Only that film, which fluttered on the grate,
Still flutters there, the sole unquiet thing.
Methinks, its motion in this hush of nature
Gives it dim sympathies with me who live,
Making it a companionable form,
Whose puny flaps and freaks the idling Spirit 
By its own moods interprets, every where
Echo or mirror seeking of itself,
And makes a toy of Thought.
But O ! how oft,
How oft, at school, with most believing mind,
Presageful, have I gazed upon the bars,
To watch that fluttering stranger! and as oft
With unclosed lids, already had I dreamt
Of my sweet birth-place, and the old church-tower,
Whose bells, the poor man's only music, rang
From morn to evening, all the hot Fair-day, 
So sweetly, that they stirred and haunted me
With a wild pleasure, falling on mine ear
Most like articulate sounds of things to come!
So gazed I, till the soothing things, I dreamt,
Lulled me to sleep, and sleep prolonged my dreams!
And so I brooded all the following morn,
Awed by the stern preceptor's face, mine eye
Fixed with mock study on my swimming book:
Save if the door half opened, and I snatched
A hasty glance, and still my heart leaped up, 
For still I hoped to see the stranger's face,
Townsman, or aunt, or sister more beloved,
My play-mate when we both were clothed alike!
Dear Babe, that sleepest cradled by my side,
Whose gentle breathings, heard in this deep calm,
Fill up the intersperséd vacancies
And momentary pauses of the thought!
My babe so beautiful! it thrills my heart
With tender gladness, thus to look at thee,
And think that thou shalt learn far other lore, 
And in far other scenes! For I was reared
In the great city, pent 'mid cloisters dim,
And saw nought lovely but the sky and stars.
But thou, my babe! shalt wander like a breeze
By lakes and sandy shores, beneath the crags
Of ancient mountain, and beneath the clouds,
Which image in their bulk both lakes and shores
And mountain crags: so shalt thou see and hear
The lovely shapes and sounds intelligible
Of that eternal language, which thy God 
Utters, who from eternity doth teach
Himself in all, and all things in himself.
Great universal Teacher ! he shall mould
Thy spirit, and by giving make it ask.
Therefore all seasons shall be sweet to thee,
Whether the summer clothe the general earth
With greenness, or the redbreast sit and sing
Betwixt the tufts of snow on the bare branch
Of mossy apple-tree, while the nigh thatch
Smokes in the sun-thaw; whether the eave-drops fall 
Heard only in the trances of the blast,
Or if the secret ministry of frost
Shall hang them up in silent icicles,
Quietly shining to the quiet Moon.
Hartley will ‘see and hear’ [line 58] God’s eternal language in all seasons … There in an ambivalence in his gesture of blessing, since it is others who read nature’s language. In the final version of ‘Frost at Midnight’ Coleridge returns to the ‘deep calm’  on the winter midnight, but in an earlier version he returned to the ‘dead calm’, a troubling indication that Hartley’s role is not simply that of a second self, but of someone granted a blessing that Coleridge cannot share.It's astute of Magnuson, I think, to recognise the extent to which this poem records not harmony so much as a sort of chasm existing between Coleridge and his son. Indeed, the verse's calmness of tone is a little baffling: is it the deep peacefulness of a contented spirit, or the blankness of a despairing soul who has, even if only temporarily, accepted his hopelessness, and deferred hope onto the life of his son? We all know what hope deferred maketh of the heart.
So: a poem about fatherhood and sonhood, and it takes its starting point in religiously-inflected thoughts about a frost, at midnight. Since the poem so clearly, even ostentatiously, indicates that this is a matter of specific personal observation (Coleridge actually sitting in his cottage at midnight, actually watching the fire, actually peering through the window at the frost outside) it might look perverse to pursue a literary source. Nonetheless that's what I'm going to do.
I'm going to do so because I am surprised, even to the point of astonishment, critics have missed that the phrase 'frost at midnight' itself is a Biblical tag. Well, maybe astonishment oversells it. To register the allusion we need to turn to the Vulgate, which not everybody is in the habit of doing: nocte gelu (there is no specific Latin word for 'midnight' as opposed to 'night'; the one is folded into the other, semantically). Genesis 31:40:
Die aestu consumebar et nocte gelu, fugiebatque somnus ab oculis meis.Here's the KJV's translation: 'Thus I was; in the day the drought consumed me, and the frost by night; and my sleep departed from mine eyes', which I'm going to tweak, without departing from the meaning of the Latin (and I daresay the original Hebrew), to emphasise my point: 'Thus I was: in the day the drought consumed me, and the frost at midnight; and my sleep departed from mine eyes'.
Chapter 31 of Genesis has to do with the relationship between Laban and Jacob. As I'm sure you know, Laban was Jacob's uncle, with whom the patriarch-to-be lived for twenty years. The deal was originally supposed to be: Jacob would serve his uncle seven years and at the end get to marry Laban's daughter Rachel as reward; but after seven years Jacob is instead tricked into marrying Leah. So Jacob agrees to work for Laban a further seven years in order to be able to marry Rachel as well. Finally, six years after his 14-year-stint was supposed to have ended, Jacob snuck away from his uncle, taking his wives and all his kine with him. Good word, kine. In Genesis 31 Laban comes after Jacob, and despite dream-warnings from God not to hassle him, catches up with him near Gilead. He rebukes Jacob: 'Wherefore didst thou flee away secretly, and steal away from me; and didst not tell me, that I might have sent thee away with mirth, and with songs, with tabret, and with harp?' [Genesis 31:27]. This makes me rethink whether the 'secret' part of Coleridge's frost secret ministry might not carry with it the sense of something stealing away, something retreating. In reply Jacob upbraids Laban:
36 And Jacob was wroth, and chode with Laban: and Jacob answered and said to Laban, What is my trespass? what is my sin, that thou hast so hotly pursued after me?The encounter ends well: Jacob builds a pillar out of stones as a kind of altar (he says to his uncle '"Now therefore come thou, let us make a covenant, I and thou; and let it be for a witness between me and thee." And Jacob took a stone, and set it up for a pillar'). Laban goes back home and Jacob goes on to his destiny, which is to change his name to Israel and become the father of the twelve tribes.
37 Whereas thou hast searched all my stuff, what hast thou found of all thy household stuff? set it here before my brethren and thy brethren, that they may judge betwixt us both.
38 This twenty years have I been with thee; thy ewes and thy she goats have not cast their young, and the rams of thy flock have I not eaten.
39 That which was torn of beasts I brought not unto thee; I bare the loss of it; of my hand didst thou require it, whether stolen by day, or stolen by night.
40 Thus I was; in the day the drought consumed me, and the frost at midnight; and my sleep departed from mine eyes.
41 Thus have I been twenty years in thy house; I served thee fourteen years for thy two daughters, and six years for thy cattle: and thou hast changed my wages ten times.
42 Except the God of my father, the God of Abraham, and the fear of Isaac, had been with me, surely thou hadst sent me away now empty. God hath seen mine affliction and the labour of my hands, and rebuked thee yesternight.
If we situate the text in this context, or even perhaps read Coleridge's poem as an oblique gloss upon this Biblical passage, what does it tell us? Well, presumably Coleridge is the Laban-figure here and Hartley the Jacob. This might point up the ambiguity of Coleridge's feelings of paternal affection and his desire to protect. To quote Wikipedia, Laban is often taken as 'symbolizing those whose concern for the welfare of their immediate family, nominally a virtue, is taken to the point where it has lasting negative ramifications.' Even as he promises to look after his son, Coleridge is tacitly conceding the dangers of being over-protective. And the fact that Laban is an uncle, and father-figure, rather than an actual father speaks perhaps to Coleridge's buried uncertainties about his own paternal role. 'Frost at Midnight' is a poem that expects a better life for the son than the father had; and that frames its covenant—for covenant this poem assuredly is—in terms of a fort-da journey out in the direction of the son that circles round to a frosty return. 'And early in the morning,' this chapter of Genesis end, 'Laban rose up, and kissed his sons and his daughters, and blessed them: and Laban departed, and returned unto his place.'
In the Genesis passage the frost at midnight is an affliction Jacob has had to undergo, rather than an environment that prompts Laban to thought (although I suppose we might say that Jacob bringing it to Laban's attention makes him think about it). I wonder if the parching 'heat at the daytime' is in some sense behind Coleridge's first, slightly wrong-footing remembrance of his childhood 'hot Fair-day' which is almost immediately replaced by his later memory of boarding in London at Christ's Hospital? And I wonder if the heap of coals in his grate is connected in some sense with the heap of stones Jacob assembles as correlative to his covenant with Laban: 'And Jacob said unto his brethren, Gather stones; and they took stones, and made an heap ... And Laban said to Jacob, Behold this heap, and behold this pillar, which I have cast betwixt me and thee; This heap be witness, and this pillar be witness, that I will not pass over this heap to thee, and that thou shalt not pass over this heap and this pillar unto me, for harm' [Genesis 31:46-52]. It is, in other words, the heap of stones that establishes the principle of 'being strangers' as a guarantee of no harm. And when Coleridge imagines Hartley wandering 'beneath the crags/Of ancient mountain' [60-61], a rather oddly singular mountain, is he on some level thinking of Gilead, the mountain at the foot of which Laban and Jacob reconciled and made their covenant? Gilead in Hebrew means both the 'eternal joy' of God and the 'eternal stone' or 'eternal memorial'. That might be why Coleridge's otherwise unnamed mountain embodies 'the lovely shapes and sounds intelligible/Of that eternal language, which thy God/Utters, who from eternity doth teach/Himself in all, and all things in himself'.