The answer
During the Divine Liturgy we should have in mind that our Lord Jesus Christ is the Sacrifice, the Altar and the Priest who is offering the sacrifice on the altar. In the prayers for the Fathers we pray saying "Their prayers ….do receive upon Your holy, heavenly and rational altar" the word "rational" here means 'understanding'. This refers to the Son of God Who is the Logos, the Word of God and the Understanding of God.Answered by His Eminence Metropolitan Youssef (opens in a new tab)