“As to [the evidence of the value of knowledge in] the sayings of the Companions (al-āthār), Ali ibn-abi-Talib said to Kumayl, ‘O thou perfect of knowledge! Knowledge is better than riches; for knowledge guardeth thee whereas thou guardest riches. Knowledge governs while riches are governed. Riches diminish with spending but knowledge increases therewith.’ And again. ‘The learned is superior to the fasting, praying and self-mortifying man. Should the learned die, a gap would be created in Islam [by his death] and no one would fill this gap save one of his successors.’ ‘Ali said:

‘Learning is the glory of mankind,
The wise are beacons on the road to truth;
Man is worth his knowledge, nothing more—
The fool will be his inveterate foe,
Knowledge is man’s hope of life immortal,
Man may die but wisdom liveth ever.’”

~ Imam Al-Ghazali

Ihya Ulum al-Din, The Book of Knowledge, translated by Nabih Amin Faris (1988).