Wisdom 16:11 (WEB)
For they were bitten to put them in remembrance of your oracles, and were quickly saved, lest, falling into deep forgetfulness, they should become unable to respond to your kindness.
Catechism · 1
“Nevertheless, already in the Old Testament, God ordained or permitted the making of images that pointed symbolically toward salvation by the incarnate Word: so it was with the bronze serpent, the ark of the covenant, and the cherubim.” — Catechism footnote: Cf. Num 21:4-9; Wis 16:5-14; Jn 3:14-15; Ex 25:10-22; 1 Kings 6:23-28; 7:23-26.