The book of Colossians was written in part to combat some errors that the church at Colosse had. These errors ranged from relativism, to Platonic reasoning (things in heaven are good and all matter is evil), to angel worship and Gnosticism (believing you needed special, secret knowledge). Paul wanted to keep the church at Colosse away from these false lines of reasoning.
No doubt people had left the church at Colosse and had begun to follow a bastardized version of Christianity or had abandoned the faith altogether. They weren't leaving the Baptist church and going to the Lutheran church down the street, they were leaving Christianity. This had to have hurt Paul's heart deeply. In fact, you can see this in his letter in chapter one.
"For this reason, since the day we heard about you, we have not stopped praying for you and asking God to fill you with the knowledge of His will through all spiritual wisdom and understanding." Colossians 1:9
Paul heard about the strife in Colosse and the heresies that had invaded the church and had torn people away from it. He wrote that since he heard about it he prayed continuously for them. Paul was torn up inside and went to God on behalf of the church at Colosse.
I find it interesting to read what Paul prayed for the people of the church at Colosse. He prayed that God would fill them with knowledge of His will through all spiritual wisdom and understanding. Now, the Gnostics were all about knowledge, but Paul was not talking about secret knowledge. The church had already been given all the knowledge they needed for salvation. There is no secret knowledge needed to be a Christian. 4-year-olds playing with Play-Doh and 60-year-olds with a Ph.D. can both understand the Gospel and accept it.
So why did Paul ask that God give them knowledge?
The other night as we studied this passage in Bible study, my friend Kat made a great point and I'll paraphrase it. Paul prayed that they would have knowledge because if they really had knowledge they would not leave the church.
See, many people in the church at Colosse were leaving the church and the Gospel for something different and "better". Paul knew that if they only knew, really knew they would never leave. If they only knew the Gospel they would never leave it. Jesus said a similar thing when He gave the parable of the soils. The one that hears and understands was the one that was saved. We can't just hear the Gospel we must understand it.
To understand the Gospel you don't have to be a rocket scientist. No, all intellect levels can understand the Gospel. When we understand the Gospel, really understand it, we will be unshakeable. When we understand all that the Gospel wins us, all that the Gospel saves us from, when we understand what we have we will never abandon it.
If I said to you, "All you have to do is stand on this street corner until I come back sometime today and I'll bring you $100 million." You would stay there, right? If you left it would mean that you didn't believe I was coming back or you didn't understand what I was saying. Now, if I came back and saw that you left and then found you and asked, "Why did you leave?" you would say, "I didn't understand that you actually were coming back. I thought it was a prank or scam." You wouldn't leave the street corner because it got a little rainy. You wouldn't leave because your friend asked you to go to lunch. No, getting a little wet is worth $100 million. Missing lunch with a friend is worth $100 million.
Understand the Gospel, really understand it. Look at the promises of Scripture. Search through all of what the Gospel accomplishes for you. Examine all that awaits you if you don't have the Gospel. Do this because if you only knew you would hold fast to the Gospel. Many things will help keep you faithful to the Gospel, but nothing will keep you more faithful to the Gospel than the Gospel itself. Know the Gospel and stay faithful today.