It says Bereishis (50,15) לו ישטמנו יוסף והשב ישיב לנו את הרעה, if Yosef will hate us, he will repay all the bad,
says the midrash והשב זה יוסף, ישיב זה עשו, vehashev, repay refers to Yosef an then Eisov will have some excuse to repay us. The Yaaros Devash explains that Eisov can only fall in the future into Yosef’s hand because the brothers hated him but he did not repay them but Eisov has repaid Yaakov. However if Yosef will repay his brothers for their hatred, Eisov will have an excuse for his actions and therefore, will not be able to fall into Yosef’s hand.