Jacob's seventh son was by Zilpah, Leah's handmaid. His tribe had their place with Simeon and Reuben on the south side of the tabernacle during the march through the wilderness. The tribes of Reuben and Gad continued all through their history to follow the pastoral pursuits of the patriarchs. The portion allotted to the tribe of Gad was on the east of Jordan, and comprehended the half of Gilead, a region of great beauty and fertility, bounded on the east by the Arabian desert, on the west by the Jordan, and on the north by the river Jabbok. It thus included the whole of the Jordan valley as far north as to the Sea of Galilee, where it narrowed almost to a point. This tribe was fierce and warlike and bore witness to the prophecy of Jacob.
When Leah saw that she had stopped having children, she took her maidservant Zilpah and gave her to Jacob as a wife. Leah's
servant Zilpah bore Jacob a son. Then Lean said, "What good fortune!" So she named him Gad. (Genesis 30:9-11)
Gad will be attacked by a band of raiders, but he will attack them at their heels (Genesis 49:19)