God intends the included to tell others

As an Apostle Paul was a steward, appointed by God to be a voice piece of the riches of Christ to all humankind, especially the non-Jewish people in the regions he traveled. And he was the steward of what he called a “mystery of Christ.”

A mystery in the NT sense does not mean something fuzzy, or unclear, or uncertain. Instead, “mystery” is a technical term that refers to a truth that has not previously been made known, and in many cases a truth, which because of its character, can never be grasped, or understood by the unaided human intellect or by mere human ability.