John Calvin Commentary Colossians 2:10

"and in him ye are made full, who is the head of all principality and power:" — Colossians 2:10 (ASV)

And ye are complete in him. He adds that this perfect essence of Deity, which is in Christ, is profitable to us in this respect: that we are also perfect in him. “As for God’s dwelling wholly in Christ, it is so that we, having obtained him, may possess an entire perfection in him.” Those, therefore, who do not rest satisfied with Christ alone, do injury to God in two ways; for besides detracting from the glory of God by desiring something above his perfection, they are also ungrateful, since they seek elsewhere what they already have in Christ. Paul, however, does not mean that the perfection of Christ is transfused into us, but that there are in him resources from which we may be filled, so that we may lack nothing.

Who is the head. He has introduced this clause again because of the angels, meaning that the angels also will be ours, if we have Christ. But more on this later. Meanwhile, we must observe this: that we are hemmed in, above and below, with railings, so that our faith may not deviate even to the slightest extent from Christ.