John Donne (24 January 1572 - 31 March 1631 / London, England)

Now thou hast loved me one whole day,
Tomorrow when thou leav'st, what wilt thou say?
Wilt thou then antedate some new-made vow?
    Or say that now
We are not just those persons which we were?
Or, that oaths made in reverential fear
Of love, and his wrath, any may forswear?
Or, as true deaths, true marriages untie,
So lovers' contracts, images of those,
Bind but till sleep, death's image, them unloose?
    Or your own end to justify,
For having purposed change, and falsehood, you
Can have no way but falsehood to be true?
Vain lunatic, against these 'scapes I could
    Dispute, and conquer, if I would,
    Which I abstain to do,
For by tomorrow, I may think so too.