The speaker looks ahead to when the young man is forty, imagining time as a besieging army that leaves deep trenches across his once-praised face. That admired beauty, he warns, will wilt into a tattered, worthless scrap. If someone then asks where all that splendor has gone, pointing to the hollows of his own worn eyes would be a shameful, greedy answer — a praise that devours itself. There’s a much better reply, he insists: “This fair child of mine.” The child would tally up the father’s beauty and excuse his aging, proving that loveliness continues through succession. The mood is urgent and quietly fierce, blending the violent image of winter’s siege with a tender longing for legacy. Beneath the warning runs a real sadness at inevitable decay, but the closing couplet offers a defiant warmth — the comfort of seeing your own blood pulse warmly in a child just when you feel yours turning cold.
Sonnet 2: When forty winters shall besiege thy brow — Summary
When forty winters shall besiege thy brow, And dig deep trenches in thy beauty's field, Thy youth's proud livery so gazed on now, Will be a tatter'd weed of small worth held: Then being asked, where all thy beauty lies, Where all the treasure of thy lusty days; To say, within thine own deep sunken eyes, Were an all-eating shame, and thriftless praise. How much more praise deserv'd thy beauty's use, If thou couldst answer 'This fair child of mine Shall sum my count, and make my old excuse,' Proving his beauty by succession thine! This were to be new made when thou art old, And see thy blood warm when thou feel'st it cold.