We can't see God because he's invisible. But we can see what he does. Balloons are filled with air that we can't see, but we see the balloon get big as the air is put in. Radio waves are invisible, but they exist. Just because we can't see God doesn't mean he isn't real. Believing that God is there even though we can't see him is faith. Someday, in heaven, we will see God face to face.
We can see and understand only a little about God now. It is like we were looking at his reflection in a poor mirror. Someday we are going to see him face to face. Now all that I know is hazy and blurred. But then I will see everything clearly. I will see as clearly as God sees into my heart right now. (1 Corinithians 13:12)
John 1:18; Colossians 1:15; 1 Timothy 1:17; Hebrews 11:27
Note to Parents
Young children struggle with this because of their concrete way of thinking. Using illustrations like the ones here are helpful, but still imperfect; we can't see air because its molecules don't form a solid enough image for us to see, not because it has no physical form. In contrast, God is invisible to us because he is a spirit.