Why we stay on knees praying? I think we are preparing for God’s security system.
In presence of God embodied in a body, one should stay on knees to make for him inconvenient to attack God’s body.
However: (Rom. 14:4) “Who are you who judge another’s servant? To his own lord he stands or falls. Yes, he will be made to stand, for God has power to make him stand.” This means that God’s security system is revealed so good (“God has power”) that the need to stay on the knees eliminates.