By falling with his face to the ground Joshua shows the appropriate respect that an inferior should pay to a superior (see Ruth 2:10; 2 Samuel 9:6 ; 2 Samuel 14:22; 2 Chronicles 20:18).1 The fact that the stranger does not rebuke him for his actions suggests that he is worthy of worship (cf. Acts 14:12–15; Revelation 19:10).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?”