He is the image of the invisible God, the firstborn over all creation. For by Him all things were created that are in heaven and that are on earth, visible and invisible, whether thrones or dominions or principalities or powers. All things were created through Him and for Him. And He is before all things, and in Him all things consist. And He is the head of the body, the church, who is the beginning, the firstborn from the dead, that in all things He may have the preeminence. Colossians 1:15-18 (NKJV)
In other words Christ is the highest and greatest. Everything heads up in Him, all things are concluded in Christ. He is above and over all things in authority and power. Jesus Christ is God Most High, He is God Almighty. He co-shares with the Father and the Holy Spirit the essence and all the attributes of God. He is to be served and worshipped.
To have Him is to have everything worthwhile. To know Him is to know everything worth knowing, it is attaining to the highest knowledge. To depend on Him is to be the strongest and most powerful. To trust in Him is to be the wisest. To believe and unite with Him is to find your true self and truly live to the fullest.