Midrash Vayisau

Midrash Vayisau is one of the smaller midrashim. This small midrash, "the heroic legend of the sons of Jacob", is based on Genesis 35:5 and 36:6, and recounts the story of the wars of Jacob and his sons against the kings of the Amorites and against Esau and his Edomite army.
The earliest attestation of Midrash Vayisau appears in Bereshit Rabbati, attributed to R. Moshe ha-Darshan of Narbonne.
The beginning of its discussion of the Amorite war is as follows: "Our teachers said that although they did not pursue after them this time, yet seven years later all the kings of the Amorites gathered themselves together against the sons of Jacob."