14And he said, “No; but I am the commander of the army of the LORD. Now I have come.”And Joshua fell on his face to the earth and worshiped and said to him, “What does my lord say to his servant?”
This answer suggests that the interests of this man are not the same as the interests of Joshua.1 He has not come to help Israel but to take control of the battle. This emphasizes that the battle belongs to the Lord and Israel needs to submit to the Lord’s command.2
14 And he said, “No; but I am the commander of the army of the LORD. Now I have come.” And Joshua fell on his face to the earth and worshiped and said to him, “What does my lord say to his servant?”