On the Mountain of the Transfiguration, God speaks from the cloud, as he had done on Sinai. But now he says: “This is my beloved Son; listen to him” (Mk 9:7). He commands us to listen to his Son, because “no one knows the Father except the Son and anyone to whom the Son chooses to reveal him” (Mt 11:27). And so we learn that the true name of God is FATHER! The name which is beyond all other names: ABBA! (cf. Gal 4:6). And in Jesus we learn that our true name is SON, DAUGHTER! We learn that the God of the Exodus and the Covenant sets his people free because they are his sons and daughters, created not for slavery but for “the glorious liberty of the children of God” (Rom 8:21).
-Blessed John Paul II’s homily on Mt. Sinai, February 2000