As gold, when united with iron, losses its purity and cannot shine, so Knowledge, when existing with attachment to earthly objects and such other shortcomings, fails to display its splendour.
लोहयुक्तं यथा हेम विपक्वं न विराजते। तथापक्वकषायाख्यं विज्ञानं न प्रकाशते॥