en_tn/mat/05/39.md

But I say

one who is evil

"an evil person" or "someone who harms you"

strikes ... your right cheek

To strike the side of a man's face was an insult in Jesus' culture. As with the eye and the hand, the right cheek is the more important one, and striking that cheek was a terrible insult.

strikes

hits with the back of an open hand

turn to him the other also

"let him hit your other cheek also"