Testament of Gad 6:6
Testament of the Twelve Patriarchs[Let not another man hear thy secrets when engaged in legal strife, lest he come to hate thee and become thy enemy, and commit a great sin against thee; for ofttimes he addresseth thee guilefully or busieth himself about thee with wicked intent.] And though he deny it and yet have a sense of shame when reproved, give over reproving him. For he who denieth may repent so as not again to wrong thee; yea, he may also honour thee, and [fear and] be at peace with thee And if he be shameless and persist in his wrong-doing, even so forgive him from the heart, and leave to God the avenging.
Romans 12:17
15 Rejoice with those who rejoice, weep with those who weep. 16 Live in harmony with one another; do not be haughty but associate with the lowly. Do not be conceited. 17 Do not repay anyone evil for evil; consider what is good before all people. 18 If possible, so far as it depends on you, live peaceably with all people. 19 Do not avenge yourselves, dear friends, but give place to God’s wrath, for it is written, “Vengeance is mine, I will repay,” says the Lord. 20 Rather, if your enemy is hungry, feed him; if he is thirsty, give him a drink; for in doing this you will be heaping burning coals on his head. 21 Do not be overcome by evil, but overcome evil with good.
Notes and References
"... Testament of Gad 6:7 urges forgiveness even of the one wllo persists in wrongdoing, adding, "and leave vengeance to God" {Charlesworth 1983, 1 :816). The hymn that concludes the Community Rule found at Qumran includes these lines (1QS 10:17, Vermes 1995, 85): I will pay no man the reward of evil; I will pursue him with goodness. For judgment of all things is with God and it is He who will render to man his reward. In this whole legacy, vengeance is forbidden, not because it is morally destructive, but because it pre-emts the role of God ..."
Keck, Leander E. Romans (pp. 307-309) Abingdon Press, 2005