The Kenites were an ancient people living near the land of Canaan around the time of Abraham (Genesis 15:18–21). The Bible mentions several dealings between the Israelites and the Kenites, who were always on friendly terms with each other.
Moses’ father-in-law, Jethro, also known as Reuel, was “the priest of Midian” and a Kenite (Judges 1:16). Jethro lived south of Canaan near Mount Sinai (Exodus 3:1). When Moses fled from Egypt, he went to Midian, where he right away met Jethro’s seven daughters, all shepherdesses. Moses eventually wed one of them, a woman named Zipporah (Exodus 2:16–21) and thus married into the Kenite tribe. Moses lived among the Kenites for many years before God called him as the one to deliver the Israelites from their enslavement in Egypt.
It seems that the Kenites in Midian knew enough about the one true God to maintain a priest. The name Reuel means “friend of God.” After the exodus, Reuel’s knowledge of God dramatically increased, and he joined Moses and Aaron in bringing a burnt sacrifice and other offerings before the Lord to worship Him (Exodus 18:9–12).
It is probable that the Kenites and the Midianites were related in some way. Reuel lived in Midian when Moses met him. Also, in Numbers 10:29, Moses’ father-in-law is called “Reuel the Midianite” (elsewhere, he is called a Kenite). Scripture also links the Kenites to the tribe of the Rekabites (1 Chronicles 2:55).
The Kenites were friendly to Moses and the Israelites during the time of the exodus. It seems that Jethro, Hobab, and other Kenites joined with Moses and traveled all the way to Canaan with the people of God (Exodus 18:1–7; Numbers 10:29–33). The Kenites settled near Jericho until they eventually moved south to live in the desert region of Negev (Judges 1:16; cf. 1 Samuel 27:10). However, a Kenite named Heber stayed in Canaan, migrating north to near Kedesh. It was Heber’s wife, Jael, who killed Sisera during the time of Deborah and Barak (Judges 4:11, 17–23). During King Saul’s reign, God instructed Israel to destroy the Amalekites. But mercy was shown to the Kenites who lived among the Amalekites; before Saul attacked, “he said to the Kenites, ‘Go away, leave the Amalekites so that I do not destroy you along with them; for you showed kindness to all the Israelites when they came up out of Egypt.’ So the Kenites moved away from the Amalekites” (1 Samuel 15:6).
There are some who claim that the Kenites were descendants of Cain, due to the similarity between the Hebrew words translated "Cain" and "Kenite." However, unless someone in Noah’s family was a descendant of Cain, all of Cain’s descendants would have been wiped out in the Flood. Further, even if a member of Noah’s family was a descendant of Cain, there would be no way, post-Flood, for a distinct line of Cain to re-emerge. For example, if Ham’s wife was a descendant of Cain, all of Ham’s descendants would be descendants of Cain. With that said, the important point is this: the Bible nowhere connects the Kenites with Cain.