Charles Ellicott Commentary Malachi 3:6

"For I, Jehovah, change not; therefore ye, O sons of Jacob, are not consumed." — Malachi 3:6 (ASV)

For I am the Lord, I change not. —Better, For I Jehovah change not.

Because it is the Eternal’s unchangeable will that the sons of Jacob, His chosen people, should not perish as a nation, He will purify them by the eradication of the wicked among them, that the remnant (the superior part; see Note on Malachi 2:15) may return to their allegiance. (Compare to Romans 11).

Ewald renders the words: For I, the LORD, have not changed: but you sons of Jacob, have you not altered? But the last verb does not mean “to alter;” and, moreover, the former translation is exactly in accordance with the wording of the prayer in Ezra 9:14-15.