Joshua 5:13-15

And it came to pass, when Joshua was by Jericho, that he lifted his eyes and looked, and behold, a Man stood 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?” So He said, “No, but as Commander of the army of the LORD I have now come.” And Joshua fell on his face to the earth and worshiped, and said to Him, “What does my Lord say to His servant?” Then the Commander of the LORD’s army said to Joshua, “Take your sandal off your foot, for the place where you stand is holy.” And Joshua did so.