Romans 16:25-26

Now to Him who is able to establish and strengthen you [in the faith] according to my gospel and the preaching of Jesus Christ, according to the revelation of the mystery [of the plan of salvation] which has been kept secret for long ages past, but now has been disclosed and through the prophetic Scriptures has been made known to all the nations, according to the commandment of the eternal God, leading them to obedience to the faith