Jamieson, Fausset & Brown

Ye--the Jews, to whom I have given predictions, verified by the event; and in delivering whom I have so often manifested MY power (see Isa 43:3-4; Isa 44:8). and my servant--that is, the whole Jewish people (Isa 41:8). believe--trust in. formed--before I existed none of the false gods were formed. "Formed" applies to the idols, not to God. Rev 1:11 uses the same language to prove the Godhead of Jesus, as Isaiah here to prove the Godhead of Jehovah.