Standing was the normal position for worship in the early church and remained so for over a thousand years. It symbolized the fact that Christians had risen with Christ and for that reason could stand before the Throne of God. It was also regarded as an expression of joy.� Standing is also an expression of respect. It is out of respect that we stand and face both the clergy and the cross as they enter into the church. This custom is based on common practice in our social life. In law courts, all the people rise when the judge enters.
Sitting, except for the clergy, did not come into usage until about the fourth century. St. Augustine was perhaps the first one to allow it and then only for the sermon. No seats were provided for the people. If they could not stand, they leaned on canes or reclined on the floor. Pews for sitting are a relatively late innovation. Today it is customary to sit for all the Scripture lessons, except the Gospel , and for the singing of lengthy psalms and hymns. But even in the singing of psalms, the congregation rises for the Gloria Patri.
Kneeling is the natural expression of repentance, humility and the feeling of one's littleness before the Holy Triune God. For that reason it is the desirable posture for the confession of sins and for prayers. Kneeling is also the expression of adoration such as in receiving the Lord's Body and Blood in the Sacrament of the Altar. [Paul H.D. Lang Ceremony and Celebration, Concordia Publishing House., St. Louis. MO 1965] One also may kneel and say prayers before the Service begins and also in preparation before receiving the body and blood of Christ in the Sacrament of the Altar or in saying a prayer of thanks after receiving Christ's body and blood in the Sacrament of the Altar.