And my tears, make a heavenly Lethean * flood,
And drown in it my sins' black memory.
That thou remember them, some claim as debt;
I think it mercy, if thou wilt forget.
*In Greek mythology, Lethe // (Greek: Λήθη, Lḗthē; Ancient Greek: [lɛ́:tʰɛː], Modern Greek: [ˈliθi]) was one of the five rivers of the underworld of Hades. Also known as the Ameles potamos (river of unmindfulness), the Lethe flowed around the cave of Hypnos and through the Underworld, where all those who drank from it experienced complete forgetfulness. Lethe was also the name of the Greek spirit of forgetfulness and oblivion, with whom the river was often identified.
In Classical Greek, the word lethe literally means "oblivion", "forgetfulness", or "concealment". It is related to the Greek word for "truth", aletheia (ἀλήθεια), which... means "un-forgetfulness" or "un-concealment"