દોંગા જોઈ ડરવું નહીં, પાતળા જોઈ લડવું નહીં.

dōṁgā jōī ḍaravuṁ nahīṁ, pātaḷā jōī laḍavuṁ nahīṁ.

Literally: Do not be afraid upon seeing a large person, and do not fight upon seeing a thin person.
What it means: Physical appearance is deceptive; do not judge someone's strength or courage by their size.

ગુજરાતી કહેવતસંગ્રહ (Gujarati Kahevat Sangrah) (1923) ગુજરાતી કહેવતસંગ્રહ (Gujarati Kahevat Sangrah) (1921) · read from the scan by machine — the Gujarati itself is unchecked · English is machine-made and nobody has checked it yet

Heard it differently, or know we've got the sense wrong? Tell us — that is exactly the kind of correction this needs.