Reference for Psalms 57:4

יִשְׁלַ֤ח מִשָּׁמַ֨יִם ׀ וְֽיוֹשִׁיעֵ֗נִי חֵרֵ֣ף שֹׁאֲפִ֣י סֶ֑לָה יִשְׁלַ֥ח אֱ֝לֹהִ֗ים חַסְדּ֥וֹ וַאֲמִתּֽוֹ׃

He will send from heaven, and save me, when he that would swallow me up taunteth, Selah; God shall send forth His mercy and His truth.

ספר השרשים