Only by the Spirit can we learn Christ
The natural spirit, the purely human spirit, the spirit that is not yet holy cannot grasp the deep meaning of Christ. It is almost like expecting a canary in a cage to learn Shakespeare. He cannot do so. You would have to put your own brain inside of the canary’s brain. So the brain of a scientist or dramatist cannot understand the mysteries of redemption because it lacks the Spirit. As St. Paul puts it, “The natural man receiveth not the things of the Spirit of God, for they are foolishness unto him. And neither can he know them because they are spiritually discerned.” Trying to teach people about Christ and the mysteries of our holy faith is almost like trying to teach a blind man color, unless those people are ready to receive the Spirit of Christ himself. Now converts who take instruction come to know that Jesus is the Lord. Where do they learn it? From the Spirit. One becomes interested in the Church simply because he received a grace that illumined his mind and strengthened his will. The Holy Spirit does that. The Holy Spirit woos the soul, draws it into closer fellowship, to more intimate union.