All human things are subject to decay,
And, when fate summons, monarchs must obey.

The couplet expresses a classical memento mori: everything human—power, institutions, bodies, reputations—inevitably deteriorates with time. The second line sharpens the point by singling out monarchs, the apparent pinnacle of worldly authority, to insist that even they are compelled to submit when “fate” (death, providence, historical necessity) calls. In Dryden’s idiom, “fate” can carry both pagan and Christian resonances, but the moral is consistent: political sovereignty does not confer exemption from mortality or decline. The lines thus function as a sober corrective to pride and a reminder of the limits of human grandeur.