GOD, the strength of all theym that trust in thee, mercifully accept our prayers; and because the weakenes of oure mortall nature can do no good thyng without thee, graunt us the helpe of thy grace, that in kepyng of thy commaundementes we may please thee, both in will and dede; through Jesus Christ our lorde.
The First Sunday after Trinity is the Sunday in the Octave of Corpus Christi. Modern revisions in the year made by the Holy See have now transferred the feast of Corpus Christi to the Sunday. Cranmer here translated the collect from Sunday in the Gelasian Sacramentary as prescribed in the Sarum Missal.
In his story The Great Divorce, C.S.Lewis has a vision of inhabitants of Hell on a daytrip to Heaven. These folk find themselves to be utterly insubstantial in the blessed realm. Although we are not in Hell, we are perhaps at our most insubstantial now - imperfect, incomplete, merely shades of what God created us to be, and it is now that we have the opportunity to rectify this. At the moment, we try to please God, but, through the flimsiness of our being, the works of goodness slip through the vapour that constitutes our fingers. We need substance in order to serve God.
It is therefore a great comfort to us that God offers us that substance in the Eucharist. As we consume the Body of Christ, we are provided with the substance of God which fleshes out our being with His flesh. It is only through His presence completing us that we can grasp hold of the goodness and love that need to be spread abroad into the world.
It doesn't matter which way we view this Sunday, because in some sense we are praying for the same thing - to become more like God in Christ. But if we examine our lives honestly, just how far have we got in this endeavour?