Shakespeare opens with a scolding, and a surprisingly severe one. "For shame!" is what you might say to a child caught being mean, yet the charge that follows is enormous: the young man addressed loves no one at all. The speaker's reasoning is neat and slightly unfair. Fine, he says, "Grant, if thou wilt, thou art belov'd of many", since being adored is easy for someone so attractive, "But that thou none lov'st is most evident." The proof is how the young man treats himself. By being "unprovident", with no care for the future, he behaves like someone who hates himself. The sonnet sits in the opening run of the sequence, where a young man is urged to have a child. Yet no word for children or marriage appears here. The argument about parenthood travels entirely by implication, which makes the accusation sound moral rather than practical.
The vocabulary comes from the courtroom. "Evident" sounds like evidence laid before a jury, "murderous hate" names the crime, and "conspire" turns the young man into a plotter whose only victim is himself. Then the imagery changes from crime to construction. His body is a "beauteous roof" that he tries "to ruinate", when his "chief desire" should be to "repair" it. A house, unlike a person's good looks, obviously needs maintenance, and a neglected one obviously falls. Without stating it, the image makes beauty feel like a property with an expiry date, and "repair" points ahead to the couplet, where the only remedy on offer is a new self.
The form is the Shakespearean sonnet: three quatrains and a couplet, rhyming ABAB CDCD EFEF GG. The first quatrain has a distinctive texture. Lines 1 and 3 end on an extra unstressed syllable ("any", "many"), and the long rhyme of "unprovident" with "evident" has a prosecutor's drumbeat to it. After that the verse tightens into short commands and questions.
The turn comes at line 9 with "O! change thy thought, that I may change my mind". Until now the speaker has been an impersonal judge, but here an exclamation and a sudden "I" admit that his verdict depends on the young man's behaviour. The repeated "change" works as a hinge and a bargain: you change, and I will too. The next line, "Shall hate be fairer lodg'd than gentle love?", reuses the house image, now with hate as an unworthy guest occupying a handsome building. The speaker wants inner nature to match outer appearance: "Be, as thy presence is, gracious and kind." "Kind" here means gentle, but it also carried the older sense of "natural" and "of one's own kin". The poem seems to lean on that doubleness as it moves toward family.
The couplet drops the legal tone for something nearer a favour asked of a friend: "Make thee another self for love of me". The phrase "for love of me" is easy to miss, but it shows that the speaker has a stake in the outcome. The final line, "That beauty still may live in thine or thee", is neatly open. "Thine" may mean a child or something of the young man's own, while "thee" is the man himself. The sentence is built so that either outcome saves beauty.
The sonnet matters because of the way it makes an argument move. A familiar piece of advice becomes a small drama of accusation, concession, hinge and plea. The central paradox is also memorable. Self-love is normally the vice, but here the real failure of self-regard is declining to continue oneself. And the voice behind the reasoning gradually stops sounding like a lawyer and starts sounding like someone who cannot bear to see something lovely wasted.