In righteousness — It is what I will faithfully perform. Return — Without effect. It is a metaphor from ambassadors, who sometimes return to their princes without any success in their business. Every tongue — Not only the Jews, but all nations.
Related Commentaries of Isaiah 45:23
Isaiah 45:23
23 I have sworn by myself, the word is gone out of my mouth in righteousness, and shall not return, That unto me every knee shall bow, every tongue shall swear.