Genesis 8:20 And Noah built an altar to Jehovah and took of every clean beast and of every clean bird and offered burnt offerings on the altar.
The altar is a type of the cross of Christ, and the offerings are types of the different aspects of Christ. The building of an altar and the offering of offerings on it signify the offering of Christ to God through the cross. In the church life, the first thing we must do is not to work for God but to go to the cross to be terminated; then we need to experience Christ and offer to God the Christ whom we have experienced in different aspects for God's satisfaction.