Joshua 5:13-15

Now it came about when Joshua was by Jericho, that he lifted up his eyes and looked, and behold, a man was standing opposite him with his sword drawn in his hand, and Joshua went to him and said to him, “Are you for us or for our adversaries?” He said, “No; rather I indeed come now as captain of the host of the LORD.” And Joshua fell on his face to the earth, and bowed down, and said to him, “What has my lord to say to his servant?” The captain of the LORD’S host said to Joshua, “Remove your sandals from your feet, for the place where you are standing is holy.” And Joshua did so.