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.
I have sworn by myself - equivalent to, "As I live," as Romans 14:11 quotes it. So Numbers 14:21. God could swear by no greater, therefore swears by Himself (Hebrews 6:13; Hebrews 6:16).
The word is gone out of my mouth (in) righteousness - or 'the truth ( tsªdaaqaah (H6666)) (note, Isaiah 45:19) is gone forth from my mouth, the word (of promise), and it shall not return (i:e., which shall not be revoked') (Lowth). But the accents favour the English version. Literally, 'there is gone out of my mouth the righteousness-word.'
Unto me every knee shall bow, every tongue shall swear - namely, an oath of allegiance to God as their true King (note, Isaiah 19:18; Isaiah 65:16). Yet to be fulfilled (Zechariah 14:9).