וַיִּשָּׂ֨א דָוִ֜יד אֶת־עֵינָ֗יו וַיַּ֞רְא אֶת־מַלְאַ֤ךְ יְהוָה֙ עֹמֵ֗ד בֵּ֤ין הָאָ֙רֶץ֙ וּבֵ֣ין הַשָּׁמַ֔יִם וְחַרְבּ֤וֹ שְׁלוּפָה֙ בְּיָד֔וֹ נְטוּיָ֖ה עַל־יְרוּשָׁלִָ֑ם וַיִּפֹּ֨ל דָּוִ֧יד וְהַזְּקֵנִ֛ים מְכֻסִּ֥ים בַּשַּׂקִּ֖ים עַל־פְּנֵיהֶֽם׃
Mishneh Torah, Leavened and Unleavened Bread
"And with an outstretched forearm" - this [refers to] the sword, as it is stated (I Chronicles 21:16); "And his sword was drawn in his hand, leaning over Jerusalem."