But we are bound to always give thanks to God for you, brothers loved by the Lord, because God chose you from the beginning for salvation through sanctification of the Spirit and belief in the truth;
and belief of the truth: The truth here, as in the preceding verse, is the gospel of Jesus Christ. Paul’s message is that being chosen by God depends upon our believing and obeying the truth. God calls us by the gospel; and if we obey the gospel, then through this means He has chosen us. The word "belief" (pistis) means "faith in God of which Jesus Christ is the author" (Thayer 513-1-4102). The word "truth" (aleethia) means "the truth, as taught in the Christian religion, respecting God and the execution of his purpose through Christ, and respecting the duties of man" (Thayer 26-2-225).