Judges 6:17 And he said unto him, if now I have found grace in thy sight, then shew me a sign that thou talkest with me.
The Angel of the Lord (Jesus) had just appeared to Gideon and told him that he would deliver Israel from the Midianites. Gideon’s response to God’s presence and His call was to protest that he was a common man and unworthy. And although he knew it was the Lord he couldn’t really believe it. He needed to be sure, so he asked for a sign to convince him that it was really God speaking to him. So the Angel touched the rock with his staff and burned with fire the offering Gideon prepared. The Lord condescended to the human’s limitations and gave a sign. Gideon was convinced: he said, “Alas, Oh Lord God, for because I have seen an angel of the Lord face to face.”
Man does not see God and so does not believe Him. Even if God or an angel should appear to us in real life we could still doubt, for it could be an apparition or an illusion. Satan can even appear as an angel of light. Jesus did indisputable signs and wonders and many still could not believe Him.
We have the Word of God, and that is enough. Abraham said to the rich man in hell: “If they do not hear Moses and the Prophets, neither will they be convinced if someone should rise from the dead.” The Word and the Sacraments are the signs that the Lord has chosen to show us. The Holy Spirit uses these means to convince. He calls us by the Gospel to create faith. Faith sees!
Jesus answered the seekers: “This is the work of God, that you believe in him whom he hath sent.” Though we do not need visible signs to believe, as the word and Spirit are enough, He does send signs into our lives occasionally to reinforce the faith He already granted. Look for them!