If one were to meet God face to face, the familiar greeting, "What do You do?" would likely not be the first inquiry. Rather "Who are You?" might well be the primary response to the magnitude of His glorious Person.
Unto Moses, the Lord identified Himself as "I Am" rather than as "I Do" (Ephesians 3:14). This is not to minimize His wondrous acts on display throughout creation and in our lives. "One generation shall praise Thy works to another, and shall declare Thy mighty acts. I will speak of the glorious honor of Thy majesty, and of Thy wondrous works" (Psalm 145:4-5). However, doings are the fruit and expression of being. God does what He does because He is who He is. "The deep things of God," as the Apostle Paul referenced, most pointedly concern the character and nature of One whose depths even eternity will not suffice in completely fathoming (I Corinthians 2:10).
Born again believers in the Lord Jesus Christ are privileged to often ask the great question - "Lord, who are You?" - with great expectation that our Father in Heaven loves both our inquiries and His provision of answers. He will lead us to the Scriptures for illumination - "In Thy light shall we see light" (Psalm 36:9). His Holy Spirit will quicken our hearts and minds with insight - "The Comforter, which is the Holy Spirit, whom the Father will send in My name, He shall teach you all things" (John 14:26). And in the brothers and sisters in Christ with whom we share our lives, the person of our triune God will be known as His Divine character and nature is manifested in human personalities - "I will dwell in them, and walk in them" (II Corinthians 6:16).
This day is a wonderful day to ask the great question. As will be tomorrow, and the next day, and throughout the timeless glory of a forever that will not be long enough to fully plumb the depths of God's infinity. "Lord, who are You?" The Heart and Mind of Heaven will be increasingly revealed in our own hearts and minds as it thrills us to ask the question, and as it thrills God to answer.
"I... cease not to give thanks for you, making mention of you in my prayers; that the God of our Lord Jesus Christ, the Father of glory, may give unto you the Spirit of wisdom and revelation in the knowledge of Him."