Responding to a Slap
Setting of the quotation (Ex. 21:24, Lev. 24:20, Deut. 19:21) was public, the court of law. The Pharisees were trying to apply this in a private setting. How can a right-handed man slap another on the right cheek? Backhanded, indicating insult and challenge. Christ says dont respond to this in anger, rather with acceptance.