નદીનું મૂળ ને ઋષિનું કુળ જોવાય નહીં.

nadīnuṁ mūḷa nē r̥ṣinuṁ kuḷa jōvāya nahīṁ.

Literally: The source of a river and the lineage of a sage should not be examined.
What it means: One should judge great things or people by their current state rather than digging into their humble origins.

Also said as

ગુજરાતી કહેવતસંગ્રહ (Gujarati Kahevat Sangrah) (1923) · 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.