Matthew 5:33-48 (ESV)
33 “Again you have heard that it was said to those of old, ‘You shall not swear falsely, but shall perform to the Lord what you have sworn.’34 But I say to you, Do not take an oath at all, either by heaven, for it is the throne of God, 35 or by the earth, for it is his footstool, or by Jerusalem, for it is the city of the great King. 36 And do not take an oath by your head, for you cannot make one hair white or black. 37 Let what you say be simply ‘Yes’ or ‘No’; anything more than this comes from evil. 
38 “You have heard that it was said, ‘An eye for an eye and a tooth for a tooth.’ 39 But I say to you, Do not resist the one who is evil. But if anyone slaps you on the right cheek, turn to him the other also. 40 And if anyone would sue you and take your tunic,  let him have your cloak as well. 41 And if anyone forces you to go one mile, go with him two miles. 42 Give to the one who begs from you, and do not refuse the one who would borrow from you.
Love Your Enemies
43 “You have heard that it was said, ‘You shall love your neighbor and hate your enemy.’ 44 But I say to you, Love your enemies and pray for those who persecute you, 45 so that you may be sons of your Father who is in heaven. For he makes his sun rise on the evil and on the good, and sends rain on the just and on the unjust. 46 For if you love those who love you, what reward do you have? Do not even the tax collectors do the same? 47 And if you greet only your brothers,  what more are you doing than others? Do not even the Gentiles do the same? 48 You therefore must be perfect, as your heavenly Father is perfect.