On the contrary, we speak God’s hidden wisdom in a mystery, a wisdom God predestined before the ages for our glory.
1 CORINTHIANS 2:7
In the Bible when it talks about mystery, it means some hidden truth that God has. The hidden mystery is that God had a plan from the very beginning, that God so loved the world that He would send His only begotten Son, that whoever believed in His only begotten Son would be saved.
So God's hidden mystery was that throughout history, He was gonna call a people. Out of that people, they were gonna have a lineage of His people that were supposed to bless the world, and they would bless the world, because out of 2 branches of that family would come a guy named Joseph and a lady named Mary. And Mary would be a virgin and she would have a baby without a man's seed. Now, that's a miracle, right? It's not possible unless God does it.
And Jesus was born of a virgin. That means He was the only one ever born with a mother but not a father. Why?Because the father had sinned, and out of that, the seed of sin was passed onto every one of us. The reason you are bound for Hell apart from Jesus is because you have a father. If you have a father, you inherited the sin nature through the seed of the man.
And so now, here's a virgin-born baby. That baby lives a perfect life, unlike all the rest of us who sin. He becomes the second Adam. The first Adam sinned. He's the second Adam, He doesn't sin. He lives a perfect life. He dies on a cross, shedding His perfect blood as the Lamb of God. He's taken down after He says, "It is finished. Into Thy hands I commend my spirit." He dies, they put His body in the grave, and on the third day He rises from the dead.
This was the mystery that nobody understood. The Jewish people didn't understand it. All the rulers, Paul says it...
None of the rulers of this age knew this wisdom, for if they had known it, they would not have crucified the Lord of glory.
1 CORINTHIANS 2:8
Why? Because all of those powers and rulers, those fallen angels, those divine council members of God that chose to move away from Him with Satan - God had a mystery so those rulers, those spiritual rulers, wouldn't know what God was doing. He shared it through the prophets in various ways that we can now see, but ultimately, they didn't know, so they crucified Jesus.
Little did they know, by crucifying Jesus, they were sealing with His blood, with His death, their own defeat forever and ever and ever. Because it was a mystery that had to do with the plan of God, that God had a plan to save all of us by His Son dying on a cross, shedding His blood, and rising again to victory so whoever believes in Him would have the mystery, mysterion in the Greek, revealed to them so now you understand it.
And you can see that God's been working from the very beginning when Adam and Eve, in their pride, took the fruit and sinned, and sin was passed on all the way to the day you were born and you were a sinner. And Jesus has already died while we were yet sinners. Paul said in Romans He died on that cross so that now our eyes are open, our ears are open .It's entered into our heart through the Spirit of God what God has done.
