Exodus 25:19 (WEB)
Make one cherub at the one end, and one cherub at the other end. You shall make the cherubim on its two ends of one piece with the mercy seat.
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.
