“I am God, I change not; therefore ye sons of Jacob are not consumed.”-Malachi 3:6

Now, who are “the sons of Jacob,” who can rejoice in an immutable God?

First, they are the sons of God’s election; for it is written, “Jacob have I loved, and Esau have I hated, the children being not yet born neither having done good nor evil.” It was written, “The elder shall serve the younger.” “The sons of Jacob”-

“Are the sons of God’s election,
Who through sovereign grace believe;
Be eternal destination
Grace and glory they receive.”

God’s elect are here meant by “the sons of Jacob,”-those whom he foreknew and fore-ordained to everlasting salvation.

By “the sons of Jacob” are meant, in the second place, persons who enjoy peculiar rights and titles. Jacob, you know, had no rights by birth; but he soon acquired them. He changed a mess of pottage with his brother Esau, and thus gained the birthright. I do not justify the means; but he did also obtain the blessing, and so acquired peculiar rights. By “the sons of Jacob” here, are meant persons who have peculiar rights and titles. Unto them that believe, he hath given the right and power to become sons of God. They have an interest in the blood of Christ; they have a right to “enter in through the gates into the city;” they have a title to eternal honors; they have a promise to everlasting glory; they have a right to call themselves sons of God. Oh! there are peculiar rights and privileges belonging to the “sons of Jacob.” ~ C.H. Spurgeon

http://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0001.cfm