Rom 14:10-12 (AKJV/PCE)
(14:10) But why dost thou judge thy brother? or why dost thou set at nought thy brother? for we shall all stand before the judgment seat of Christ. (14:11) For it is written, [As] I live, saith the Lord, every knee shall bow to me, and every tongue shall confess to God. (14:12) So then every one of us shall give account of himself to God.

This is the passage that Paul is quoting from:

Isa 45:21-23 (AKJV/PCE)
(45:21) Tell ye, and bring [them] near; yea, let them take counsel together: who hath declared this from ancient time? [who] hath told it from that time? [have] not I the LORD? and [there is] no God else beside me; a just God and a Saviour; [there is] none beside me. (45:22) Look unto me, and be ye saved, all the ends of the earth: for I [am] God, and [there is] none else. (45:23) 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.


Again Paul says this in Philippians:

Phil 2:9-11 (AKJV/PCE)
(2:9) Wherefore God also hath highly exalted him, and given him a name which is above every name: (2:10) That at the name of Jesus every knee should bow, of [things] in heaven, and [things] in earth, and [things] under the earth; (2:11) And [that] every tongue should confess that Jesus Christ [is] Lord, to the glory of God the Father.