Why does Gideon ask for a sign?
Judges -24 Gideon replied, 'If now I have found favor in your eyes, give me a sign that it is really you talking to me... The angel of God said to him, 'Take the meat and the unleavened bread, place them on this rock, and pour out the broth.' And Gideon did so. With the tip of the staff that was in his hand, the angel of the LORD touched the meat and the unleavened bread. Fire flared from the rock, consuming the meat and the bread. And the angel of the LORD disappeared. When Gideon realized that it was the angel of the LORD, he exclaimed, 'Ah, Sovereign LORD! I have seen the angel of the LORD face to face!' But the LORD said to him, 'Peace! Do not be afraid. You are not going to die.' So Gideon built an altar to the LORD there and called it The LORD is Peace. To this day it stands in Ophrah of the Abiezrites.
Gideon asked for a sign that it really was God that was sending him. Probably fair enough too if you put yourself in his shoes... he was being asked to fight against and defeat the entire Midian army! You certainly would want to be sure wouldn't you? Gideon will ask again for a sign before the chapter is out, and again God will graciously respond. We always need to remember that Gideon is not some extraordinary man. He was an ordinary man from an ordinary family in an ordinary tribe. Quite like you and me actually. He was weak enough to cause God to chose him, and obedient enough to follow God's call even amidst doubt and uncertainty. With the divine fire of acceptance falling upon Gideon's offering, it suddenly dawns upon Gideon that he is speaking, face to face, with God! The appearing of the angel of the Lord is not just any old angel but is the pre-incarnate 'goings forth' of the Lord Jesus Himself! The angel however tells Gideon that he can be at peace and should not fear. And God would say the same thing to you today if you have faith in Jesus and take the time to ask! (And listen of course...)
... God knows Gideon and you for that matter, better than you know yourself. He knows we are weak and fearful creatures at times and doesn't expect perfection. The lesson and challenge for us however from this passage (especially if you are quite a fearful person) is to not allow your fear to prevent you from being obedient. Easily said I know. But God takes us and teaches us step by step if we will trust Him. Gideon, being weak like us, was fearful, but he still obeyed God's command. You would do well to ask God about this.