Matthew 13:35
that the word might be fulfilled which was spoken by the prophet, saying: I will open my mouth in parables; I will utter things that have been kept secret from the foundation of the world.
Matthew 13:11-15
He answered, and said to them: Because it is given to you to know the mysteries of the kingdom of heaven; but to them it is not given.
Luke 12:3
Wherefore, what you have spoken in the darkness, shall be heard in the light; and what you have spoken in the ear in closets, shall be proclaimed upon the house-tops.
2 Corinthians 3:12
Since then we have such hope, we use great plainness of speech,