The Jerahmeelites - i. e. the descendants of Jerahmeel, the son of Hezron, the son of Perez, the son of Judah (marginal references). They were therefore a portion of the “south of Judah.”
The Kenites - See Numbers 24:21 note; Numbers 4:11; and for their near neighborhood to Amalek, see 1 Samuel 15:6.