From a co-worker:
“Why is posture so important, then? Because it expresses the emotion tied to prayer. For example, the early Church Father Tertullian said that kneeling reflects humility and repentance, while standing expresses joy and confidence (as in confidence in the resurrection or in God’s love and mercy). Origen describes early Christians praying, whether kneeling or standing, with their arms out to their side, slightly elevated (known as the orans position). To these early Christians, prayer was a bodily act. Posture was necessarily connected to one’s ability to pray in a spirit of humility and reverence. They believed the Apostle Paul was serious when he said in his letter to the Corinthian Christians, “Honor God with your body” (1 Cor. 6:20, NIV). Now, some might say ‘God knows what is in my heart so my outward actions shouldn’t matter.’ This argument is only half true. God does know what is in our hearts, but what is in our hearts should be manifested in our actions.”
I’m stealing the argument in the last two sentences. It’s brilliant.