10 Then is completed the entire mystery of the assumed manhood, And you being dead through your trespasses and the uncircumcision of your flesh, you I say, did He quicken together with Him, having forgiven you all your trespasses, blotting out the bond written in ordinances, that was against us, which was contrary to us; and He has taken it out of the way, nailing it to the cross, and having put off from Himself His flesh, He has made a show of powers, triumphing over them in Himself. The worldly man cannot receive the faith of the Apostle, nor can any language but that of the Apostle explain his meaning.
God raised Christ from the dead; Christ in Whom the fullness of the Godhead dwelt bodily. But He quickened us also together with Him, forgiving us our sins, blotting out the bond of the law of sin, which through the ordinances made aforetime was against us, taking it out of the way, and fixing it to His cross, stripping Himself of His flesh by the law of death, holding up the powers to show, and triumphing over them in Himself. Concerning the powers and how He triumphed over them in Himself, and held them up to show, and the bond which he blotted out, and the life which He gave us, we have already spoken. But who can understand or express this mystery?
The working of God raises Christ from the dead; the same working of God quickens us together with Christ, forgives our sins, blots out the bond, and fixes it to the cross; He puts off from Himself His flesh, holds up the powers to show, and triumphs over them in Himself. We have the working of God raising Christ from the dead, and we have Christ working in Himself the very things which God works in Him, for it was Christ who died, stripping from Himself His flesh. Hold fast then to Christ the man, raised from the dead by God, and hold fast to Christ the God, working out our salvation when He was yet to die.
God works in Christ, but it is Christ Who strips from Himself His flesh and dies. It was Christ who died, and Christ Who worked with the power of God before His death, yet it was the working of God which raised the dead Christ, and it was none other who raised Christ from the dead but Christ Himself, Who worked before His death, and put off His flesh to die.
Source: On the Trinity (New Advent)