to the heart; the heart then issues its directives to the brain, for the brain supervises the nerves and the rest of the body. In this sense the brain is a mere servant of the heart: it receives what the heart dispatches to it and conveys what the heart seeks to send out. Matters thus pass from the heart to the brain and back again, and it is the brain that sets the body in motion—so when the brain is impaired, everything is impaired.

The Prophet ﷺ next said, “It is enough evil for a person to despise his Muslim brother.” In other words, were a Muslim guilty of no other wrongdoing than belittling, demeaning, and humiliating his brother, that alone would suffice as a sin—may Allah protect us. In this statement lies the strongest deterrent against looking down on your fellow Muslim; you are obliged to respect and honor him for the Islam and faith he bears.

He ﷺ also said, “The whole of a Muslim is inviolable to another Muslim—his blood, his wealth, and his honor.” “His blood” means you must not attack a Muslim by killing, wounding, or harming him in any way. “His wealth” means you may not seize his property, whether by force, theft, betrayal, false claim, or any other means; it is categorically unlawful for you to take your brother’s wealth without right. “And his honor” means you must not violate his reputation by speaking about him among the people, whether what you say is true or false. For when the Prophet ﷺ was asked about backbiting, he explained, “It is to mention your brother in a manner he dislikes.” They said, “O Messenger of Allah, what if what I say about my brother is actually in him?” He replied, “If what you say is true, you have back-bitten him; if it is not true, you have slandered him.”