1 Jn 1:1-2, 1 Cor 2:7-8, 2 Tim 1:9-10, Rom 16:25-26, Eph 3:9-11

The secret that God had hidden from before the foundation of the world was revealed. It is that Jesus is the Christ. (Col 1:26-27, 1 Jn 1:1-2, Rom 16:25-26)

Col 1:26 Even the mystery which hath been hid from ages and from generations, but now is made manifest to his saints: 27 To whom God would make known what is the riches of the glory of this mystery among the Gentiles; which is Christ in you, the hope of glory:

1 Jn 1:1 That which was from the beginning, which we have heard, which we have seen with our eyes, which we have looked upon, and our hands have handled, of the Word of life; 2 (For the life was manifested, and we have seen it, and bear witness, and shew unto you that eternal life, which was with the Father, and was manifested unto us;)

Rom 16:25 Now to him that is of power to stablish you according to my gospel, and the preaching of Jesus Christ, according to the revelation of the mystery, which was kept secret since the world began, 26 But now is made manifest, and by the scriptures of the prophets, according to the commandment of the everlasting God, made known to all nations for the obedience of faith:

Even before the foundation of the world, God prepared to save us through Jesus, the Christ. (2 Tim 1:9-10, Eph 3:9-11)

2 Tim 1:9 Who hath saved us, and called us with an holy calling, not according to our works, but according to his own purpose and grace, which was given us in Christ Jesus before the world began, 10 But is now made manifest by the appearing of our Saviour Jesus Christ, who hath abolished death, and hath brought life and immortality to light through the gospel:

Eph 3:9 And to make all men see what is the fellowship of the mystery, which from the beginning of the world hath been hid in God, who created all things by Jesus Christ: 10 To the intent that now unto the principalities and powers in heavenly places might be known by the church the manifold wisdom of God, 11 According to the eternal purpose which he purposed in Christ Jesus our Lord:

Had they known that Jesus was the Christ, the Jews would not have killed him. (1 Cor 2:7-8)

1 Cor 2:7 But we speak the wisdom of God in a mystery, even the hidden wisdom, which God ordained before the world unto our glory: 8 Which none of the princes of this world knew: for had they known it, they would not have crucified the Lord of glory.