"So, too, in matters affecting a person's relations with his fellow, as soon as there rises from his heart to his mind any animosity or hatred, G-d forbid, or jealousy, anger, or a grudge and the like, he allows them no entrance into his mind and will. On the contrary, his mind exercises its authority and power over the feelings in his heart to do the very opposite, namely, to conduct himself towards his fellow with the quality of kindness and a display of abundant love to the extreme limits, without becoming provoked into anger, G-d forbid, or to revenge in kind, G-d forbid, but rather to repay the offenders with favors, as taught in the Zohar, that one should learn from the example of Yosef [Joseph] towards his brothers."
Tanya ch 12
"A certain heathen came to Shammai and said to him, Make me a proselyte, on condition that you teach me the whole Torah while I stand on one foot. Thereupon he repulsed him with the rod which was in his hand. When he went to Hillel, he said to him, What is hateful to you, do not do to your neighbor: that is the whole Torah; all the rest of it is commentary; go and learn."
Hillel the Elder, Talmud, Shabbat 31a (~100 AC)
"Thou shalt not avenge, nor bear any grudge against the children of thy people, but thou shalt love thy neighbour as thyself: I am the LORD."