Burns begins by turning down the whole tradition of heroic verse. Let other poets boast of "scars" and sing of wars, "the plagues of human life". He will celebrate the man "wha multiplies our number". The central idea is a cheerful reversal of values: fathering children is a nobler achievement than killing, and natural desire is something to honour, not something to be ashamed of. The joke starts early. War is reduced to men with "sword and gun" who "slap mankind like lumber", as if people were planks to be knocked about, and the epic hero ends up looking like a vandal.
To back up this claim, Burns lets Nature herself speak, and she sounds a lot like the God of Genesis. "Be fruitful and increase" is a command, not a suggestion, and she has "pour'd" the "liquid fire of strong desire" into every bosom. The imagery of fire and water runs through the poem. Desire is a "flaming current", a "sacred torrent", something no sensible person would try to "stem". Fire and flood are mixed together, which suits a force that is both warm and overwhelming. The language of religion is used with a straight face, and that is where the humour lies. The bard is "all devout" and pays "obedience due", as though he were a dutiful churchgoer and not a man following his appetites.
The hero is Burns himself, seen from outside. He calls himself "a lowly bard" singing "artless strains" in "Coila's plains", Coila being the poem's name for his home district. The modesty is playful, since the poem is far from artless. The garden imagery gives it away: Beauty is a "blossom", and "Propitious Powers" shield "the young flow'rs / From mildews of abortion", as if luck were a gardener keeping blight off the seedlings. Then comes the punchline, "a double portion". The phrase sounds like a biblical inheritance, and in context it seems to hint at twins, though that is an inference from the text. The word "reward" shows the poem's logic: the more he multiplies, the more virtuous he is.
The form helps the comedy. Each eight-line stanza opens with a steady, ballad-like alternation of longer and shorter lines (ABAB), then speeds up. The later lines carry internal rhymes ("fun" and "gun", "name" and "fame", "fire" and "desire") that make the verse skip along. Each stanza ends on a pair of bouncy double rhymes, such as "lumber" and "number", "bosom" and "blossom", "current" and "torrent", and "abortion" and "portion". Double rhymes are a classic comic device, and here they also seem to act out the theme, since the sounds keep pairing off and multiplying. Language works the same way. Scots words like "wha", "meikle", "auld", "cantie" and "lang" sit beside grand phrases like "Propitious Powers" and "Ye Powers of peace". The mismatch between homely speech and high rhetoric puffs up a family occasion into something ceremonial.
The last two stanzas make that ceremony explicit. "Auld cantie Coil" is asked to count the day each year when it returns, the "third of Libra's equal sway", the day "that gave another Burns". The father hopes this son will "emulate his sire" with "more poetic fire". The fire from Nature's speech reappears, now as creative energy, so physical and poetic power are treated as the same gift. The closing stanza turns into a patriotic toast: may Coila "prop the land", and may "Burnses spring, her fame to sing, / To endless generations!" The plural "Burnses" is a delightful piece of nonsense, a surname made to multiply like the people it counts.
The poem matters because it shows Burns's gift for arguing a point while laughing at himself. Underneath the joking is a real conviction that ordinary life, with its love, children and community, deserves the same dignity that older poetry gave to battles. He makes that case in the voice of a sermon and a toast, and the poem's charm comes from how far he is willing to stretch a small domestic event to prove it.