For this reason we also, since the day we heard it, do not cease to pray for you, and to ask that you may be filled with the knowledge of His will in all wisdom and spiritual understanding; that you may walk worthy of the Lord, fully pleasing Him, being fruitful in every good work and increasing in the knowledge of God (Colossians 1:9-10).
In Colossians 1:9-10, the Apostle Paul twice emphasizes the vital important of knowledge - "knowledge of His will" and "increasing in the knowledge of God." In both cases the Greek word Paul uses is not gnosis, mere general knowledge, but epignosis: precise and correct knowledge; authentic knowledge; confirmed and tested knowledge; knowledge that conveys understanding - not merely the accumulation of facts about Christ, but a true grasp of the significance of those facts.
By contrast, Romans 1:28 says that unbelievers do not even like to retain God in their knowledge. The sense of the original Greek is that the unbelieving mind has tested God against the false standard of human wisdom, and has declared that it rejects God - "God does not meet my standards." And so, Paul says, God has given unbelievers over to a reprobate mind. In the original language, the sense is that God has given them over to the control of a mind that would not even meet the test of measuring up to the purpose for which a mind was meant.
Someone once said that a mind is a terrible thing to waste, and that is exactly what the unbeliever does by rejecting God. It is spiritual madness, and it leads to all other forms of madness. We see the evidence all around us.
Growing in knowledge of Jesus Christ and His Word is the Christian's stability in a world gone mad. It is the distinctive mark of the Christian, and the foundation of godly living. This knowledge, as Paul says in Philippians 3:10, must be our primary pursuit: "that I may know Him."