While Esau was deprived of his blessing from his father Isaac, for his younger brother Jacob had deceived him and taken the blessing, he starts to hate his brother, with so much hate that he sought to kill (slay) his brother after his father’s death. The deception of Jacob brought with it hate from his brother which in turn brought the threat of death. As you can see hate in the heart turns brother against brother.

Points to ponder:
Deception brings with it death. The deception to disobey God, by the ancient deceiver, the devil (Revelation 12:9), brings with it the threat of death, for the wages of sin is death (Romans 6:23), but the gift of God is eternal life to all who chose to obey God and keep his commandments to love God above all and love mankind as themselves (Matthew 22:36-40).

When love trumps hate, deception and death have no place. If a man says, I love God, and hates his brother, he is a liar: for he that loves not his brother whom he has seen, how can he love God whom he has not seen? (1 John 4:20).

Even when it is hard to love someone, we are asked to do so, just as God did, and not hate in our hearts. It comes down to loving God, loving man, lest we be deceived. Be ye not deceived.

Genesis 27:41 (KJV)
41 And Esau hated Jacob because of the blessing wherewith his father blessed him: and Esau said in his heart, The days of mourning for my father are at hand; then will I slay my brother Jacob.