Charles Ellicott Commentary Malachi 2:10

"Have we not all one father? hath not one God created us? why do we deal treacherously every man against his brother, profaning the covenant of our fathers?" — Malachi 2:10 (ASV)

One father—that is, not Adam, Abraham, or Jacob (as various commentators have held), but God Himself (Malachi 1:6; Deuteronomy 32:6; Deuteronomy 32:18), who is the spiritual Father of the nation, and in whom they are all brothers and sisters; so that when an Israelite married a pagan woman, or divorced an Israelite wife, it was an offense against God, a “profaning the covenant of the fathers,” and a violation of the fraternal relation.

Moreover, “one God created” them for His glory (Isaiah 43:7), for the special purpose of being a witness to His unity. The admission of idolatresses into their families would be fatal to this object.