What does Psalm 33:13 mean?

God is omniscient: all-knowing, perceiving and understanding everything in all of creation. He is unlike the disinterested, disconnected deity some unbelievers perceive. He did not create the world and then absent Himself from it, allowing it to run down by itself. He is vitally involved in creation.

Hebrews 4:13 teaches: "And no creature is hidden from his sight, but all are naked and exposed to the eyes of him to whom we must give account." Near the well called Beer-lahai-roi, after the angel of the Lord appeared to Hagar, she called the name of the Lord, "You are a God of seeing" (Genesis 16:13). In Psalm 139 David testifies that he is unable to go anywhere without the Lord's knowledge. Jesus, the Son of God, also possesses omniscience, which He exercised in compliance with the Father's will. In a notable example, He saw Nathanael under a fig tree before Nathanael approached Him (John 1:48).