And because of the immense level of hatred which caused the destruction of out holy temple which was our crowning glory, so too for the extent of the time that we do not purify ourselves from this sin we cannot be redeemed, as Chazal said “You caused that I should destroy My house and burn My hall because of baseless hatred; Seek peace and be redeemed and saved, as it says “Ask about the peace of Yerushalayim!””.
And also because of the great level of importance of the commandment of “And you shall love your friend like yourself!” which is a great rule in the Torah, it is correct and fitting for a person to strengthen himself with as much strength and effort as he can muster, through constant pure and holy thoughts to remove all hatred from his own heart. Through love, brotherhood, peace and friendship he will arouse the celestial love on high and he will make peace in the lofty spheres.
A person should reflect on the fact that when the Torah commanded us that “You shall not hate your brother in your heart!”, and the commandment of “And you shall love your friend like yourself!” they were completely superfluous and unnecessary when referring to a person who is being kind to him and there is absolutely no reason to hate him. Instead, it is obvious that the commandments refer to a person with whom he is quarrelling and who seeks to do bad to him, as about such a person the Torah gave these special commandments not to hate him and instead to love him like himself. It is true, however, that this matter is difficult, to repay good in place of evil, but since the Torah commanded us to do so it is clear that a person can fulfil this commandment, as the Torah was not given to the heavenly serving angels. However, it necessitates much effort and consistent determination to think many thoughts how to remove this hatred from his heart, by reflecting that every loss or damage that has been done to him was caused and decreed by heaven for his own goodness and no other person can do either bad or good to him or to touch that which is set aside for another even by a hairsbreadth without the will of heaven. Hashem has many messengers to do that which is good in His eyes for the benefit of the person in this world or the next world. A person should reflect profoundly on these and other similar thoughts and believe in all these things with complete faith and trust, and he should constantly strengthen himself with pure thoughts to remove hatred and arouse love, and in direct proportion to the level of difficulty so too is the amount of the reward.