Song of Songs 2:9

My beloved is like a roe or a young hart: behold, he standeth behind our wall, he looketh forth at the windows, shewing himself through the lattice.

Cross-reference

Song 2:17 repeats the gazelle/stag simile, calling the beloved to return on the mountains.

Song 8:14 again compares the beloved to a gazelle/stag on mountains, urging him to hasten.

Proverbs 5:19 compares the beloved to a 'lovely deer'—the same animal imagery for a lover as SoS 2:9's gazelle.