"Here I would like to refer to the gesture which is central to worship, and one which is threatening to disappear, namely, the practice of kneeling. We know that the Lord knelt to pray (Lk 22:41), that Stephen (Acts 7:60), Peter (Acts 9:40) and Paul (Acts 20:36) did so too. The hymn to Christ in Philippians 2:6-11 speaks of the cosmic liturgy as a bending of the knee at the name of Jesus, seeing in it a fulfillment of the Isaian prophecy (Is 45: 23) of the sovereignty of the God of Israel. In bending the knee at the name of Jesus, the Church is acting in all truth; she is entering into the cosmic gesture, paying homage to the Victor and thereby going over to the Victor's side. For in bending the knee we signify that we are imitating and adopting the attitude of him who, though he was 'in the form of God', yet 'humbled himself unto death'. In this way, by combining the prophetic word of the Old Covenant and the manner of life of Jesus Christ, the Letter to the Philippians has taken up the sign of kneeling, which it regards as the appropriate posture for Christians to adopt at the name of Jesus, and has given it a cosmic significance in salvation history. Here, the bodily gesture attains the status of a confession of faith in Christ: words could not replace such a confession."
-Joseph Cardinal Ratzinger in The Feast of Faith. (Emphasis added)