Or HaChaim on Genesis 28:6/אור החיים על בראשית כ״ח:ו׳

1 וירא עשו כי ברך יצחק את יעקב, Esau saw that Isaac had blessed Jacob, etc. This verse does not seem to tell us anything new. If it were meant to tell us that this was the reason Esau took an additional non-Canaanite wife, verse eight would have sufficed for that purpose.

2We must therefore look for some meaning beyond the mere words of the verse. Esau was aware of Jacob's' departure and of its nature, i.e. that he thereby fulfilled both a commandment by his father and mother and the commandment to look for a wife. Knowing that Isaac had blessed Jacob to complete his undertaking successfully, Esau did not bother to pursue Jacob, realising that under such circumstances he would not succeed. Although Esau is reputed to have sent his eldest son Eliphaz to catch up with Jacob and to kill him (according to Rashi on Genesis 29,11), it is possible that he merely wanted to test his ability to vanquish Jacob on his journey. This scenario may have been re-enacted when the descendants of Esau (Amalek) attacked the Israelites after the latter had crossed the sea of reeds. Esau considered his son's ability to pursue Jacob successfully as greater than his own ability to do so.