of the body a hot or cold body. Although some people say that anger is the boiling of the heart’s blood, it is an attribute inhering in the angry person’s soul, distinct from the boiling of the heart’s blood. That boiling is merely its effect, for the heat of anger warms the blood until it boils. Anger originates in the soul: it is the soul that first acquires this attribute, after which it spreads to the body. The same applies to sorrow, joy, and all other states of the soul. Sorrow causes the blood to withdraw inward, which is why a sorrowful person turns pale. Sorrow is a state of the soul, but the sorrowful person feels unable to repel the misfortune that has befallen him and despairs of doing so; hence his blood retreats inward. An angry person, by contrast, feels capable of repelling the harm or exacting punishment, so his blood spreads outward.
The motion, stillness, and tranquillity attributed to the soul are not like those attributed to the body. Allah Most High says:
“Surely, in the remembrance of Allah do hearts find rest.”
Tranquillity means stillness. Al-Jawharī said: “Itma’anna al-rajul, with the verbal nouns itmi’nān and tuma’nīnah, means that the man became still.” Allah Most High says:
“O tranquil soul, return to your Lord, well pleased and pleasing to Him.”
Likewise, hearts have a serenity suited to them. Allah Most High says:
“It is He who sent down tranquillity into the hearts of the believers so that they would increase in faith along with their existing faith.”
Likewise, rayb (unease) is the soul’s movement arising from doubt. An example of this usage occurs in the hadith:
“The Prophet, may Allah bless him and grant him peace, passed by a gazelle lying curled up asleep and said, ‘Let no one disturb it.’”
It is also said, “Something about him aroused my misgivings,” and:
“Leave what makes you uneasy for what does not make you uneasy.”
He also said:
“Lying brings unease, whereas truthfulness brings tranquillity.”
He thus made tranquillity the opposite of unease. Likewise, certainty is the opposite of doubt. Certainty encompasses the meaning of