וַיְהִ֗י בִּֽהְי֣וֹת יְהוֹשֻׁעַ֮ בִּירִיחוֹ֒ וַיִּשָּׂ֤א עֵינָיו֙ וַיַּ֔רְא וְהִנֵּה־אִישׁ֙ עֹמֵ֣ד לְנֶגְדּ֔וֹ וְחַרְבּ֥וֹ שְׁלוּפָ֖ה בְּיָד֑וֹ וַיֵּ֨לֶךְ יְהוֹשֻׁ֤עַ אֵלָיו֙ וַיֹּ֣אמֶר ל֔וֹ הֲלָ֥נוּ אַתָּ֖ה אִם־לְצָרֵֽינוּ׃
E aconteceu que, estando Yehoshua em Yericho, levantou os olhos e viu um homem parado diante dele, com sua espada desembainhada na mão. Então Yehoshua foi ter com ele e lhe perguntou: "És conosco ou com nossos inimigos?"
Rashi
extended over Jerusalem In Joshua (5:13), it says: “... and behold, a man was standing opposite him with his sword drawn in his hand, etc. ’Are you for us or for our adversaries?” Joshua was standing with his back opposite his adversaries, and the angel came opposite him; therefore, he wondered and asked him, “Are you for us or for our enemies?” [Have you come] to help us since you are standing opposite me, or to help our enemies, because you are standing also opposite them? But here, since he saw the sword of the angel, which was extended over Jerusalem, he knew by himself that he had come to strike Israel.
Rabbeinu Bahya
אשר יצא לפניהם, “who is to go out ahead of them.” It means: who is to lead them in war.
ואשר יבא לפניהם ואשר יוציאם, “and who shall come in before them and who shall take them out.” The emphasis here is on the fact that the leader personally and not some deputy should always be in front. Whereas among the Gentile nations the king or top general generally remains behind the danger zone in the rear, Moses requests that the kind of leader that would be appointed should emulate him when he had faced Sichon and Og in battle at the head of the army. We know hat Moses had been in the front, why else would G’d have reassured him when He said to him not to be afraid of Og (21,34)? We know that Joshua was at the front of the army, as when the angel with his drawn sword in his hand confronted him he asked: “do you belong to us or to our enemies?” (Joshua 5,13) We also find that David was at the head of his army as reported in Samuel I 18,16: “for he would go out and come in at their head.”
ואשר יבא לפניהם ואשר יוציאם, “and who shall come in before them and who shall take them out.” The emphasis here is on the fact that the leader personally and not some deputy should always be in front. Whereas among the Gentile nations the king or top general generally remains behind the danger zone in the rear, Moses requests that the kind of leader that would be appointed should emulate him when he had faced Sichon and Og in battle at the head of the army. We know hat Moses had been in the front, why else would G’d have reassured him when He said to him not to be afraid of Og (21,34)? We know that Joshua was at the front of the army, as when the angel with his drawn sword in his hand confronted him he asked: “do you belong to us or to our enemies?” (Joshua 5,13) We also find that David was at the head of his army as reported in Samuel I 18,16: “for he would go out and come in at their head.”
Rashi
אשר יצא לפניהם ONE WHO MAY GO BEFORE THEM — not as is the way of the kings of the nations who sit at home and send their armies to battle, but as “I” have done — I who fought against Sihon and against Og, as it is said, (Numbers 21:34) “Do not fear him: “[for I have delivered him into thy hand … and thou shall do to him as thou didst unto Sihon, etc.]” and as is the way that Joshua followed, as it is said, (Joshua 5:3) “And Joshua went to him and said, Art thou for us [or for our adversaries]”. And so, too, in the case of David, it says, (I Samuel 18:16) “For he went out and came in before them” — went out at their head, and came in at their head (Sifrei Bamidbar 139:2).