Charles Ellicott Commentary Isaiah 44:5

"One shall say, I am Jehovah`s; and another shall call [himself] by the name of Jacob; and another shall subscribe with his hand unto Jehovah, and surname [himself] by the name of Israel." — Isaiah 44:5 (ASV)

One shall say, I am the Lord’s. — The words paint, like Psalm 87:4-5, the eagerness of Gentile proselytes to attach themselves to Israel.

The forms of adhesion rise in emphasis:

1. The convert declares himself to belong to Jehovah;
2. He calls upon the name of Jacob;
3. He writes upon his hand, "To Jehovah!"—brands himself, as it were, as His servant , showing that the prohibition of idolatrous marks (Leviticus 19:28) did not exclude this (Revelation 9:4);
4. He takes the name of Israel in addition to his own as a title of honour.