כָּל־אִמְרַ֣ת אֱל֣וֹהַּ צְרוּפָ֑ה מָגֵ֥ן ה֝֗וּא לַֽחֹסִ֥ים בּֽוֹ׃
Toute parole émanée de Dieu est parfaite: il est un bouclier pour ceux qui s’abritent en lui.
Rashi
Every word of God is refined Heb. צרופה, refined, and He did not write anything unnecessary. [Therefore,] I should have been careful.
Ibn Ezra
Every word of God is forged — meaning, the words of the LORD are pure words, and they are the commandments forged like pure gold, and among them are wisdom of the fear of the Name, and it is not worth it to engage in anything else. Thus do not add to its words (Prov. 30:6), you, Itiel, i.e. do not add to it nor remove from it (Deut. 13:1).
Ibn Ezra
A shield — the initial mem in magen is not part of the root, as in menagen (musician), mishberei el (divine waves).