ציטירנדיקער פּירוש אויף דברי הימים א 16:15

Quivers. Quivers in which they place arrows, as in, “Prepare the arrows, fill the quivers הַשְּׁלָטִים,”²⁹I.e. Teaching [אלף] the Torah acts as a shield [המגן]. and it corresponds to the Chamber of Hewn Stone, from where instruction goes forth, for the Torah act as a shield to Yisroel.³⁰I Divrei Hayamim 16:15. It is also possible to render that אֶלֶף הַמָּגֵן is the same as מָגֵן הָאֶלֶף, the shield of the thousand, alluding to, “the word [of the Torah] He commanded for a thousand generations.”³¹Alternatively, שלטי are shields. (Metzudas Tzion)