વહેતાં પાણી નિર્મળાં, બંધાં ગંધેલાં હોય;

vahētāṁ pāṇī nirmaḷāṁ, baṁdhāṁ gaṁdhēlāṁ hōya;

Literally: Flowing waters are pure, while stagnant waters become foul-smelling.
What it means: Constant activity, travel, and change keep a person or an institution pure and vibrant, whereas stagnation leads to corruption.

Also said as

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.