સજ્જન તુમહી ચતુર હો, કહા શિખ દેઉં તોય;

sajjana tumahī catura hō, kahā śikha dēuṁ tōya;

Literally: O good person, you yourself are clever, what advice can I give you?
What it means: Said when addressing a wise person who already knows how to act discreetly and appropriately.

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.