જખ મારવી ને જુઠું બોલવું બરાબર.

jakha māravī nē juṭhuṁ bōlavuṁ barābara.

Literally: To waste time is equal to telling a lie.
What it means: Engaging in useless, idle activities is just as bad and dishonorable as lying.

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.