Old Testament readings use the Septuagint , the Scripture the apostles quoted. Masoretic numbering shown for reference.Learn why
LXX

Isaiah 45:21

If they will declare, let them draw nigh, that they may know together, who has caused these things to be heard from the beginning: then was it told you. I am God, and there is not another beside me; a just [God] and a Saviour; there is none but me.

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