ઠગ છતાય ઠગાઈથી, ન્યાયે ન્યાયી છતાય;

ṭhaga chatāya ṭhagāīthī, nyāyē nyāyī chatāya;

Literally: A cheat is exposed by his cheating, and a just person is revealed by his justice;
What it means: Asserts that a person's true character is ultimately revealed by their actions and dealings.

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.