It was the prayer of Jesus that the men chosen out of the world to do His work would be set apart - sanctified - in the truth of God's word. And that they would be the conduits through which others might believe. Paul confirms this very fact and responsibility in his letters to the churches at Corinth and Thessalonica,

"I was with you in weakness and in fear and in much trembling, and my message and my preaching were not in persuasive words of wisdom, but in demonstration of the Spirit and of power, so that your faith would not rest on the wisdom of men, but on the power of God." (1 Corinthians 2:3-5)

"For to us [the apostles] God revealed them through the Spirit; for the Spirit searches all things, even the depths of God. For who among men knows the thoughts of a man except the spirit of the man which is in him? Even so the thoughts of God no one knows except the Spirit of God. Now we [the apostles] have received, not the spirit of the world, but the Spirit who is from God, so that we may know the things freely given to us by God, which things we also speak, not in words taught by human wisdom, but in those taught by the Spirit, combining spiritual thoughts with spiritual words." (1 Corinthians 2:10-13)

"If anyone thinks he is a prophet or spiritual, let him recognize that the things which I write to you are the Lord's commandment." (1 Corinthians 14:37)

"For this reason we also constantly thank God that when you received the word of God which you heard from us, you accepted it not as the word of men, but for what it really is, the word of God, which also performs its work in you who believe." (1 Thessalonians 2:13)