Charles Ellicott Commentary Numbers 26:29

"The sons of Manasseh: of Machir, the family of the Machirites; and Machir begat Gilead; of Gilead, the family of the Gileadites." — Numbers 26:29 (ASV)

Machir fathered Gilead.— It is stated in 1 Chronicles 7:14, and in the Septuagint of Genesis 46:20, that Machir’s mother was an Aramitess. This may account for the name given to his son, Gilead, the border land between Syria and Canaan, and the place where Laban overtook Jacob (Genesis 31:25).