We have already seen that parables speak of the secrets or mysteries of the Kingdom of Heaven (Matt. 13:11). In other gospels this is called the Kingdom of God (Mark 4:11, Luke 8:10).
It is the Kingdom that will come down from heaven, where God is seated, to earth. Under heavenly rule and hence ’the Kingdom of Heaven‘. It is a term that refers to the Tanakh (Dan. 2:44, 7:27). God has anointed His King (Ps. 2:6), Christ Jesus, the Son of David and He will rule that Kingdom.
Kingdom at hand
The message of John the Baptist and also of Jesus himself, was in the beginning, that this Kingdom had come near (Matt. 3:2, 4:17). But Israel rejected her Messiah and the Kingdom was not revealed, but hidden. That is what the parables speak about, about the period when the Kingdom would be hidden.
But when was that Kingdom hidden? Some would say: after the resurrection of Christ, or perhaps after his ascension, when he went up to heaven and a cloud took him away from the eyes of the disciples (Acts 1:9). From that moment on, he was in any case hidden from all and hidden from view.
beginning of mystery
However, we can place the beginning of the mystery even earlier, namely at the moment that Jesus began to speak in parables. In Matthew this is in chapter 13.
In the previous chapter, Jesus encounters massive rejection, especially by the leaders of the people. When He heals a man who is possessed by a demon (12:22), He is accused of doing this by the prince of the demons (12:24). It becomes clear in this chapter that Israel, through their spiritual leaders, rejects the King sent by God and that is the reason for Jesus to no longer openly proclaim the Kingdom, but to start speaking in secret (13:11-13). The parables are only explained to His disciples, who did believe.
end of mystery
The Scripture gives a clear answer to the question of when the mystery will end in the book of Revelation. In this book, as the name suggests, the Revelation of Jesus Christ (1:1) is described and the lead-up to, and beginning of, the Kingdom. There we read:
Revelation 10
7 But in the days of the voice of the seventh messenger, when he shall sound the trumpet, then also the secret of God should be finished, as he declared to his own bondmen and the prophets.
the mystery fulfilled
The mystery, or the hiddenness, is fulfilled at the beginning of the revealed Kingdom, when the thousand years begin in which Satan is bound (Rev.20:2). Then the Kingdom is established worldwide. So the parables speak of the time when it becomes clear that the Kingdom is hidden, until the moment when the mystery is fulfilled and the Kingdom is revealed.