Shakespeare’s speaker imagines a future moment when the person he loves will frown at his flaws and withdraw affection. He pictures that love like a final account being audited, with all reasons weighed. Instead of fighting this, he preemptively takes the beloved’s side. He says he’ll retreat into the knowledge of his own lack of merit, and he’ll raise his hand to testify in favor of the beloved’s right to leave. The closing couplet cuts deep: his lover has every legal right to abandon him, because he can offer no compelling reason to be loved in the first place. The mood is quietly devastated yet strangely calm, as if the speaker has already begun mourning a loss he sees as inevitable. There’s a protective self-sabotage here—if he agrees with the rejection now, perhaps the future sting will be dulled. Underneath the resignation runs a current of profound insecurity, the sense that love must always be justified and that he will never measure up.
Sonnet 49: Against that time, if ever that time come — Summary
Against that time, if ever that time come, When I shall see thee frown on my defects, When as thy love hath cast his utmost sum, Call'd to that audit by advis'd respects; Against that time when thou shalt strangely pass, And scarcely greet me with that sun, thine eye, When love, converted from the thing it was, Shall reasons find of settled gravity; Against that time do I ensconce me here, Within the knowledge of mine own desert, And this my hand, against my self uprear, To guard the lawful reasons on thy part: To leave poor me thou hast the strength of laws, Since why to love I can allege no cause.