Colossians 2:2 That their hearts may be comforted, they being knit together in love and unto all the riches of the full assurance of understanding, unto the full knowledge of the mystery of God, Christ.
At the end of 2:2 Paul speaks of the “full knowledge of the mystery of God, Christ.” The book of Ephesians is on the mystery of Christ, which is the church, the Body (Eph. 3:4). This book [Colossians] is on the mystery of God, which is Christ, the Head.
It is crucial that we know Christ not only as our Savior and Lord, but also as the mystery of God. All Christians love the Lord Jesus. The only difference among them in this matter is the degree of their love for Him.
Even a backsliding believer loves the Lord to a certain extent. How much we love the Lord depends on how much we know Him and how much we realize concerning Him. For example, a child may appreciate a little box made to contain a diamond ring more than the ring itself.
This shows that the degree of love is determined by the degree of appreciation. The more we know the Lord Jesus and appreciate Him, the more we shall love Him. Hence, we need to go on to know the Lord Jesus not only as our Savior and Lord, but also as the mystery of God.
If we would know Christ as the mystery of God, we need to have the full experience of everything covered in 2:2. If the hearts of the Colossians were comforted and knit together in love, the result would be all the riches of the full assurance of understanding, an understanding no doubt related to the mystery of God, Christ.