Charles Ellicott Commentary Revelation 16:6

"for they poured out the blood of the saints and the prophets, and blood hast thou given them to drink: they are worthy." — Revelation 16:6 (ASV)

For they have shed . . .—Better, Because they shed (not, “have shed,” but did shed, or pour out), and blood did You give them; they are worthy. “For” is to be omitted; the sentence has a startling force without it. They—i.e., those enemies of all righteousness—are worthy; they receive the due reward of their deeds.