In Prayerbook of the Bible (1940), Lutheran theologian Dietrich Bonhoeffer emphasizes what I sometimes forget: worship is sacrifice. Since no human, in his sinful condition, can offer a perfect sacrifice, only God can appease God—through the “voluntary, sinless sacrifice” of his Son. The modest and imperfect sacrifices that I bring to church are acceptable only because of what Jesus Christ did for me.
God has promised to be present in the worship service of the congregation. So the congregation conducts its worship service according to God’s order. But Jesus Christ himself has offered the perfect worship service, in that he fulfilled all the ordained sacrifices in his own voluntary, sinless sacrifice. In his own person Christ offered God’s sacrifice for us and our sacrifice for God. For us there remains only the sacrifice of praise and thanksgiving in prayers, songs, and in a life lived according to God’s commands (Ps. 15, Ps. 50). So our entire life becomes the worship service, the thank-offering. God wishes to acknowledge such a thank-offering and to show salvation to those who are thankful (Ps. 50:23). These psalms wish to teach us to become thankful to God for the sake of Christ and to praise him in the congregation with heart, mouth, and hands.