The mystery He was revealing to His chosen audience, had not been revealed for the two thousand years of the Gentiles (from Adam until Abraham), and it had not been revealed for the two thousand years of the Jews (from Abraham until Christ's First Advent). This mystery involves Christ's coming two times: at His First Coming, He came to be "the Lamb of God"; that is, to be sacrificed for sin (Jn. 1:29-36); He will be returning at His Second Coming to reign on earth as the "Lion of the Tribe of Judah" (Rev. 5:5). In addition, the period between His First Advent and His Second Advent, deals with the mystery of the Gospel (the death, burial, and resurrection of Christ - 1 Cor. 15:1-4; Rom. 16:25; Eph. 6:19); and the Church Age (Eph. 3:4-7; 5:32; Col. 1:26-2:27)! Therefore, the key to understanding the parables of Matthew 13 is that they describe the period between Christ's two Advents.
1) The Sower (Jesus) sowing the seed (the Gospel of the Kingdom) - 13:3-8; 18-23.
The Enemy (Satan) "seed thieves" stealing the seed.
2) The Sower (Jesus) sowing the Good Seed (born again believers) - 13:24-30; 36-43.
The Enemy (Satan) sowing the bad seed (tares or the merely religious).
3) The Sower (Jesus) sowing the Mustard Seed (Church growth) - 13:31-32.
The Enemy (Satan) sending "seed thieves" into the organized church.
4) The Unleavened Bread (the true Church) - 13:33.
The Leaven (false teaching of religionists corrupts the Church) Mt. 16:6, 11.
5) The Hidden Treasure (the true Church) cost Him His all - 13:44.
Jesus paid for the whole world so He could own the mysterious treasure, the Church.
6) The Pearl of Great Price (the true Church) - 13:45-46.
Jesus bought our freedom from the one who owned us, Satan (2 Cor. 4:4; Rev. 5:9).
7) The Net (the judgment at the end of the Tribulation) - 13:47-50.
The angels will separate the Sheep from the Goats (Mt. 25:31-46; Rev. 20:4; etc.).
Has the seed come to life in you?
Then rejoice, not that you are a member of a church, but that you are a child of God!