'Mysteries' in the Bible

So let a man think of us as Christ's servants, and stewards of God's mysteries.

If I have the gift of prophecy, and know all mysteries and all knowledge; and if I have all faith, so as to remove mountains, but don't have love, I am nothing.

For he who speaks in another language speaks not to men, but to God; for no one understands; but in the Spirit he speaks mysteries.