«When forty winters shall beseige thy brow,
And dig deep trenches in thy beauty’s field,».
Sonnet 2 continues the argument and plea from Sonnet 1, this time through the imagery of military, winter, and commerce. Time again is the great enemy, besieging the youth’s brow, digging trenches — wrinkles — in his face, and ravaging his good looks. Beauty is conceived of as a treasure that decays unless, through love, its natural increase — marrying and having children — is made possible.
When forty winters shall beseige thy brow,
The poet attempts to scare the young man into marrying and having children by showing him his future. When the youth is forty years old, he will be nothing but a “tottered weed” (meaning tattered garment), “of small worth held” because he will be alone and childless. The only thing the young man will have to look back on is his self-absorbed “lusty days,” empty because he created nothing — namely, no children. This barrenness of old age is symbolized in the sonnet’s last line, “And see thy blood warm when thou feel’st it cold,” and contrasts to the previous sonnet’s spring imagery.
The poet’s argument that the young man is actually hurting himself by not procreating is present in this sonnet as it was in the preceding one. This time, however, the youth’s narcissism is both physical and emotional. The poet predicts that by the time the youth turns forty years old, he will have “deep-sunken eyes,” and the shame he will feel for not having children will be an “all-eating” emotion, which recalls the phrases “Feed’st thy light’s flame” and “this glutton be” from Sonnet 1.
Again drawing on business imagery, the poet acknowledges that all he seeks is for the young man to have a child, who would immortalize the youth’s beauty. The poet does not call the act of love “increase,” as he did in Sonnet 1, but “use,” meaning investment, the opposite of “niggarding” from Sonnet 1. In line 8, he speaks of “thriftless praise,” or unprofitable praise — the term “thrift” during Shakespeare’s lifetime had various meanings, including profit and increase, which also recalls Sonnet 1.
“Proud livery” in line 3, here meaning well-tailored clothing, contrasts to “tottered weed” as the clothes of a nobleman’s servant contrast to the rags of a beggar; the phrase also refers to the youth’s outward beauty, which time devours. To refrain from marriage makes the youth guilty of narcissism and of cruelty to future generations. A “thriftless” victim of time, he is symbolized by “winters” rather than by years.
English audio from YouTube Channel Socratica
Summary from Cliffsnotes.com