Once a mystery but now revealed.
On a question to Jesus from his disciples as to why He deviated from his normal methods and ways of preaching and teaching by now speaking in parables to them, Jesus replied, “Because it has been given to you to know the mysteries of the kingdom of heaven, but to them it has not been given.… that it might be fulfilled which was spoken by the prophet, saying: “I will open My mouth in parables; I will utter things kept secret from the foundation of the world.” (Matt. 13:11, 35).
With this explanation Jesus Christ implied that there were indeed mysteries in the Old Testament dispensation, a secret that He now stands ready to reveal to those who will believe his preaching. In the New Testament the word mystery means that it is something concealed, but which is now revealed intentionally in New Testament times.