મન ઢોંગી મન ધુર્ત છે, મન મેગળ સમાન; મન સુધરે તો મિત્ર છે, નહીં તો શત્રુ સમાન.

mana ḍhōṁgī mana dhurta chē, mana mēgaḷa samāna; mana sudharē tō mitra chē, nahīṁ tō śatru samāna.

Literally: The mind is a hypocrite, the mind is cunning, the mind is like a wild elephant; if the mind is reformed it is a friend, otherwise it is like an enemy;
What it means: One's own mind can be one's greatest ally if controlled, but its uncontrolled desires make it a dangerous enemy.

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.