make him forget knowledge whose very remembrance is sweeter than the pleasure of the desire itself; or it will afford gloating satisfaction to an enemy and grief to a friend; or it will block the path to an approaching blessing; or it will produce a defect that becomes a permanent trait—for deeds beget dispositions and character.

Section
Every moral quality has a proper limit: when it crosses that limit it turns into aggression, and when it falls short it is deficiency and humiliation.

Anger has a limit: commendable courage and a proud refusal to accept baseness—this is its perfection. When it exceeds that boundary its possessor becomes oppressive and unjust; when it falls short he becomes cowardly and feels no revulsion for shameful acts.

Eagerness has a limit: securing what is sufficient for worldly affairs and obtaining what one needs from them. If it falls short it leads to disgrace and waste; if it goes beyond, it becomes ravenous greed and a craving for what is unworthy to desire.

Envy has a limit: competing for excellence and refusing to let a peer outstrip one. When it exceeds that boundary it becomes wrongdoing and injustice, accompanied by wishing for the blessing to be removed from the envied person and striving to harm him; when it falls short it is baseness, weak aspiration, and a lowly spirit.

The Prophet (peace and blessings be upon him) said, “No envy is justified except in two cases: a man to whom Allah has given wealth and he spends it until it is exhausted in the cause of truth, and a man to whom Allah has granted wisdom and he judges by it and teaches it to the people.” (1) This is the envy of emulation, by which the envier urges himself to be like