How do we know justifying faith is true?

Justifying faith is validated through the Apostolic Gospel that asserts all believers must find their righteousness through Christ alone. Paul emphasizes in Philippians 3:9 that he desires to be found in Christ, not having his own righteousness but that which comes from God through faith. Additionally, Acts 13:39 affirms that justification comes through Him, from all which one could not be justified by the law. Therefore, the truth of justifying faith is rooted in the promises of God and the faithful execution of those promises in Christ’s sacrificial work.