Trains us in faith (Hebrews; 11:1) Faith is the assurance of things believed and the assurance of things not seen.

 In fact, God does not hide Himself, He is present in all our experiences. Joseph saw this. In Genesis 39:40,41 we see Joseph in several places in different situations. God was with him in Potiphar's palace, in prisons, and in Pharaoh's palace. But Joseph did not see him. God is there even when we don't see him, only through deep faith in life's trials and sufferings. Even if the sun is forgotten by the clouds, the sun is still there. In the same way trials and tribulations may hide the presence of God from us but God has not forsaken us.