Jesus is talking to a group of people about what might happen to them as individuals. The word "you" in "You have heard" and "I say to you" is plural. The phrase "whoever strikes you" is addressed to singular "you," but you may have to translate it as plural "you." (See: [[rc://en/ta/man/translate/figs-you]])
Jesus agrees with God and his word. But, he does not agree with the way the religious leaders had applied God's word. This can be stated in active form. See how you translated this in [Matthew 5:33](./33.md). AT: "Your religious leaders have told you that God said" (See: [[rc://en/ta/man/translate/figs-activepassive]])
The "I" is emphatic. This indicates that what Jesus says is equally important to the original commands from God. Try to translate this phrase in a way that shows that emphasis. See how you translated this in [Matthew 5:22](./21.md).
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.