Christians and Muslims believe in the same God, the one God
"Along the path marked out by Abraham in his submission to the divine will, we find his descendant, the Blessed Virgin Mary, Mother of Jesus, who is also devoutly invoked by Muslims, especially in popular piety. 2. We Christians joyfully recognize the religious values we have in common with Islam. Today I would like to repeat what I said to young Muslims some years ago in Casablanca: "We believe in the same God, the one God, the living God, the God who created the world and brings his creatures to their perfection" (Insegnamenti, VIII/2, [1985], p. 497). The patrimony of revealed texts in the Bible speaks unanimously of the oneness of God. Jesus himself reaffirms it, making Israel's profession his own: "The Lord our God, the Lord is one" (Mk 12:29; cf. Dt 6:4-5). This oneness is also affirmed in the words of praise that spring from the heart of the Apostle Paul: "To the king of ages, immortal, invisible, the only God, be honour and glory for ever and ever. Amen'"(1 Tm 1:17)."
Pope John Paul II May 5, 1999
<> Matthew quotes Jesus regarding authority. We are to be obedient. We are to hear legitimate authority and obey. Doctrine is from legitimate authority. Neirther of you have liberty to reject any Doctrine. Neither of you have any "seat" of authority.
Both of you approach Catholic Doctrine as though you were Protestants. YOu usurp legitimate authority, you place yourselves on the chair of Moses.<>