Luke 18:1-8 NKJV:
"Then He spoke a parable to them, that men always ought to pray and not lose heart, saying: 'There was in a certain city a judge who did not fear God nor regard man. Now there was a widow in that city; and she came to him, saying, ‘Get justice for me from my adversary.’ And he would not for a while; but afterward he said within himself, ‘Though I do not fear God nor regard man, yet because this widow troubles me I will avenge her, lest by her continual coming she weary me.’ Then the Lord said, 'Hear what the unjust judge said. And shall God not avenge His own elect who cry out day and night to Him, though He bears long with them? I tell you that He will avenge them speedily. Nevertheless, when the Son of Man comes, will He really find faith on the earth?”
Romans 12:17-21 NKJV:
"Repay no one evil for evil. Have regard for good things in the sight of all men. If it is possible, as much as depends on you, live peaceably with all men. Beloved, do not avenge yourselves, but rather give place to wrath; for it is written, 'Vengeance is Mine, I will repay,' says the Lord. Therefore
'If your enemy is hungry, feed him;
If he is thirsty, give him a drink;
For in so doing you will heap coals of fire on his head.'
Do not be overcome by evil, but overcome evil with good."