Matthew 5:36-39

36Nor should you swear by your head, for you cannot make a single hair white or black. 37Simply let your ‘Yes’ be ‘Yes,’ and your ‘No,’ ‘No.’ Anything more comes from the evil one.1

38You have heard that it was said, ‘Eye for eye and tooth for tooth.’2 39But I tell you not to resist an evil person. If someone slaps you on your right cheek, turn to him the other also;