36 Hence the Apostle, to make his explanation of this Mystery complete, after saying that death is the last enemy to be conquered, adds: But when He says, All things are put in subjection except Him, Who did subject all things to Him, then must He be subjected to Him, that did subject all things to Him, that God may be all in all. The first step of the Mystery is that all things are subjected to Him: then He is subjected to Him, Who subjects all things to Himself. As we are subjected to the glory of the rule of His body, so He also, reigning in the glory of His body, is by the same Mystery in turn subjected to Him, Who subjects all things to Himself. And we are subjected to the glory of His body, that we may share that splendour with which He reigns in the body, since we shall be conformed to His body.
Source: On the Trinity (New Advent)