Why did Jesus address Yahweh as God at the Cross? Throughout the Gospels, we see Jesus addressing Yahweh as 'Father'. But we see at Matt 27:46 Jesus addressing the  Father as `God':


  "And about three o’clock Jesus cried with a loud voice, “Eli, Eli, lema sabachthani?” that is, “My God, my God, why have you forsaken me?”


One is eager to know the deeper meaning of that way of addressing. What do the teachings of Catholic Church say about the particular way Jesus addressed the Father just before His death at the Cross?
St. Thomas Aquinas's commentary on Matthew 27:46 explains that 


  He calls Him His Father, in that He is God; He calls Him His God, in that He is man: wherefore, when He says, My God, My God, etc., it is clear that He is speaking insofar as He is a man; hence, He groans, to express the greatness of His human suffering.