Commanding Good and Forbidding Evil is Book 19 of al-Ghazālī's Revival of the Religious Sciences, the ninth book of the Second Quarter, The Customs of Daily Life.

It is the duty most Muslims are most afraid of. Al-Ghazālī calls it the greatest pillar of the religion — then shows exactly how far it goes, and where it stops. He opens by naming this the very thing the prophets were sent for, and by mourning that in his own age its knowledge had all but vanished. Then he does what the fearful and the zealous both fail to do: he makes it precise. Four pillars — the one who reproves, the wrong, the one reproved, and the act itself — each with its conditions; eight degrees of reproving, from a quiet word to the drawing of weapons, each fenced by its own etiquette. Who may speak, when, to whom, and how hard.

If you have ever seen a wrong and said nothing, or said too much, this is the book that tells you what you should have done.

Who may reprove: not only the upright, not only those the ruler appoints, but anyone who is able. A child before his father, a subject before his ruler, a sinner who reproves another. Wrongs in mosques, markets, streets and guest-houses; speaking truth to rulers, from Abū Bakr before Quraysh to Sufyān al-Thawrī's letter to Hārūn al-Rashīd.

Book 18 asked what a sound does to a heart. This one asks what a wrong does to a community when no one names it. Silence is not neutrality. It is a choice, and it is counted.

This English is taken from the classical Arabic of the Iḥyāʾ, not rebuilt from an older translation. It can be read straight through, or studied beside the original.

Read it before the next time you look away.