Anyway, I did find a section on the Pope's homily for Holy Thursday (Maundy Thursday) where he directed us to the postures of prayer in Scripture. It was nice and short but very well written. So I pass it on to you here:
Before reflecting on the content of Jesus’ petition, we must still consider what the evangelists tell us about Jesus’ posture during his prayer. Matthew and Mark tell us that he “threw himself on the ground” (Mt 26:39; cf. Mk 14:35), thus assuming a posture of complete submission, as is preserved in the Roman liturgy of Good Friday. Luke, on the other hand, tells us that Jesus prayed on his knees. In the Acts of the Apostles, he speaks of the saints praying on their knees: Stephen during his stoning, Peter at the raising of someone who had died, Paul on his way to martyrdom. In this way Luke has sketched a brief history of prayer on one’s knees in the early Church. Christians, in kneeling, enter into Jesus’ prayer on the Mount of Olives. When menaced by the power of evil, as they kneel, they are upright before the world, while as sons and daughters, they kneel before the Father. Before God’s glory we Christians kneel and acknowledge his divinity; by that posture we also express our confidence that he will prevail.