Why were Moses, Peter, and others afraid in the Presence of GOD? Fear is not of GOD.?

God’s often speaks that the Spirit of Fear is not of GOD. However, I have noticed in the bible Moses was fearful of God at Mount Horeb when God appeared to Him as a flame of fire (Exodus 3). When Jesus went up on the mountain to pray with the three apostles they were fearful of Jesus when He was Transfigured. Fear is not of God. So, why would the prophets and others fearful in His Presence?