Jesus taught how we should act toward those who are not kind to us.

Luke 6:27-36

27 “But I say this to each of you disciples who are listening to what I say: Love your enemies as well as your friends. Do good things for those who hate you! 28 Ask God to bless those who curse you! Pray for those who mistreat you! 29 If someone insults one of you by striking you on one of your cheeks, turn your face so that he can strike the other cheek also. If a bandit wants to take away your (sg) coat, let him also have your shirt. 30 Give something to everyone who asks you (sg) for something. If someone takes away things that belong to you (sg), do not ask him to return them. 31 In whatever way you (pl) want others to act toward you, that is the way that you should act toward them.

32 If you love only those who love you, do not expect God to praise you for doing that [RHQ], because even sinners love those who love them. 33 If you do good things only for those who do good things for you, do not expect God to reward you for doing that [RHQ], because even sinners do that. 34 If you lend things or money only to those who you expect will give something back to you, do not expect that God will reward you [RHQ] for doing that. Even sinners lend to other sinners, because they expect them to pay everything back. 35 Instead, love your enemies! Do good things for them! Lend to them, and do not expect them to pay anything back! If you do that, God will give you a big reward. And you will be acting like his children should. Remember that God is kind to people who are not grateful and to people who are wicked, and he expects you to be like that too. 36 Act mercifully toward others, just like your Father in heaven acts mercifully toward you.”