Commentaire sur Le Deutéronome 19:11

וכי יהיה איש שנא לרעהו BUT IF A MAN HATE HIS FELLOW [AND LIE IN WAIT FOR HIM] — It is through his hatred that he comes to such a point as to “lie in wait for him”. From here they (the Rabbis) derived their statement: If a man transgresses a light command he will in the end transgress a weighty command; — because he transgressed the command (Leviticus 19:17) “Thou shalt not hate thy brother in thine heart”, he will in the end come to such a point as to shed blood. It is for this reason that it is stated here, apparently redundantly, “but if a man hate his fellow [and lie in wait for him]”, for it ought to have written only: “But if a man rise up and lie in wait for his fellow and smite him mortally” (Sifrei Devarim 186:2).

וכי יהיה איש שנא לרעהו, "And if there will be a man who hates his fellow, etc." This paragraph alludes to what is taught in Makkot 12 that the guardian angel of Esau, i.e. Samael, will make three errors of judgment in the future. One of them is that although the cities of refuge will provide refuge only for someone who kills inadvertently, this guardian angel is under the impression that such cities also provide refuge for intentional murderers. [The Talmud deals with an interpretation of Isaiah 63,1 assuming the prophet refers to the guardian angel of Edom, i.e. Samael who also mistakes the city Bazrah for Betzer (spelled similarly in Hebrew) and tries to take refuge there. Ed.] כי יהיה לאיש שונא, the worst enemy a person has is his evil urge, he is the root cause of all feelings of enmity. לרעהו, "against his fellow," i.e. that he represents himself as man's friend whereas in reality he means to harm you. He uses the pretense of loving you as a means to harm you. וארב לו, "and he ambushes him," i.e. he causes him to sin. You must remember that the first sin a person commits is considered as if it had been inadvertent. Having committed that sin, however, he thereby provides the evil urge with access to his soul as we know from Genesis 4,7 "that sin crouches at the entrance (to your soul)." As long as man has not sinned the evil urge is till outside the entrance. Not only that, but Satan tries to convince you that what you thought was evil is actually good. This is the worst kind of ambush one can be exposed to. The Torah continues וקם עליו, "and he rises up against him," i.e. once he has caused you to sin he now confronts you openly whereas previously he was treading very carefully, so that you almost did not notice his presence (compare Sukkah 52).

וכי יהיה איש שונא לרעהו וארב לו וקם עליו והכהו נפש, “if there will be a man who hates his fellow and he sets an ambush or him and rises up against him and strikes him fatally;” because he hates him he eventually spills his blood; he started with the relatively minor offense of hating a fellow Jew which led to the serious offense of murder (compare Sifri Shoftim 186).