אֶת אֲשֶׁר עָשָׂה לִי. שֶׁהֶרְאָה הַסֵּפֶר שֶׁשָּׁלַח דָּוִד בְּיַד אוּרִיָּה. (במדרש רבי תנחומא שם) [What] was done to me. By showing them the letter which Dovid had sent through Uryah,1Uryah was one of Dovid’s generals. Dovid wanted Uryah killed so that he could marry Bas Sheva, Uryah’s wife. With Yoav’s assistance, he arranged to have Uryah placed in the front lines of the battle. When Uryah was killed, everyone blamed Yoav. Instead of protecting Dovid, Yoav betrayed him by disclosing that it was Dovid’s plan to place Uryah in the thick of the battle in order that he be killed. [according to] the Midrash Rabbi Tanchuma.
דְּמֵי מִלְחָמָה בְּשָׁלֹם. שֶׁהָיָה לָהֶם שָׁלוֹם עִמּוֹ, וְלֹא הָיוּ נִשְׁמָרִים מִמֶּנּוּ. [And shed] the blood of war at a time of peace. Since they were at peace with him, they were not on guard against him.
בַּחֲגֹרָתוֹ אֲשֶׁר בְּמָתְנָיו. שֶׁחָגַר חַרְבּוֹ מְצֻמֶּדֶת עַל מָתְנָיו, שֶׁלֹּא כְּדֶרֶךְ הַחוֹגְרִים, בְּצֵאתוֹ לִקְרַאת עֲמָשָׂא, וּפִיהָ לְמַטָּה כְּדֵי שֶׁתִּפֹּל, כְּמָה שֶׁנֶּאֱמַר: וְהוּא יָצָא וַתִּפֹּל, וּכְשֶׁנָּפְלָה וּנְטָלָהּ, כְּסָבוּר עֲמָשָׂא שֶׁלֹּא נְטָלָהּ אֶלָּא לְהַגְבִּיהָהּ מִן הָאָרֶץ, וְלֹא נִשְׁמַר מֵהַחֶרֶב אֲשֶׁר בְּיַד יוֹאָב. On his belt which was on his loins. He had girded his sword, attached to his loins, not in the customary manner of those girding swords, when he went out to meet Amasa. [He placed the sword’s] opening downward so that it would fall out, as it is stated, “and he went out and it fell out.”2II Shmuel 20:8. Once it fell, he [Yo’av] retrieved it. Amasa presumed that he retrieved it only to pick it up from the ground, and he did not guard himself from the sword which was in Yo’av’s hand.
וּבְנַעֲלוֹ אֲשֶׁר בְּרַגְלָיו. אֶת אַבְנֵר הָרַג בְּעָרְמָה, שֶׁשְּׁאָלוֹ גִּדֶּמֶת הֵיאָךְ חוֹלֶצֶת, כְּמָה שֶׁנֶּאֱמַר: וַיַּטֵּהוּ יוֹאָב אֶל תּוֹךְ הַשַּׁעַר לְדַבֵּר אִתּוֹ 'בַשֶּׁלִי', לְשׁוֹן 'שַׁל' נְעָלֶיךָ. And in his shoe that was on his feet. He killed Avner cunningly by asking him, “How does a woman who has no hands remove the shoes?”3During חליצה, the widow must remove the shoe of her deceased husband’s brother who does not want to marry her. as it is stated, “And Yo’av caused him to turn aside at the gate to speak with him בשלי.”4II Shmuel 3:27. [בשלי is] an expression of “remove [של] your shoes.”5Shemos 3:5.