61 You who trisect Christ into the Word, the soul and the body, or degrade the whole Christ, even God the Word, into a single member of our race, unfold to us this mystery of great godliness which was manifested in the flesh. What Spirit did Christ give up? Who commended His Spirit into the hands of His Father? Who was to be in Paradise that same day? Who complained that He was deserted of God? The cry of the deserted betokens the weakness of the dying: the promise of Paradise the sovereign power of the living God.
To commend His Spirit denoted confidence: to give up His Spirit implied His departure by death. Who then, I demand, was it Who died? Surely He Who gave up His Spirit? But Who gave up His Spirit? Certainly He Who commended it to His Father. And if He Who commended His Spirit is the same as He Who gave it up and died, was it the body which commended its soul, or God Who commended the body's soul? I say 'soul,' because there is no doubt it is frequently synonymous with 'spirit,' as might be gathered merely from the language here: Jesus gave up His 'Spirit' when He was on the point of death.
If, therefore, you hold the conviction that the body commended the soul, that the perishable commended the living, the corruptible the eternal, that which was to be raised again, that which abides unchanged, then, since He Who commended His Spirit to the Father was also to be in Paradise with the thief that same day, I would fain know if, while the sepulchre received Him, He was abiding in heaven, or if He was abiding in heaven, when He cried out that God had deserted Him.
Source: On the Trinity (New Advent)