one that knows the truth, loves it, and prefers it to all else. Its disease consists either in doubting the truth or in preferring something else to it.

The disease of the hypocrites is one of doubt and uncertainty, while the disease of the disobedient is one of waywardness and desire. Allah, glorified is He, has called both of these a disease.

Ibn al-Anbārī said: The basic linguistic meaning of disease is corruption. To say that someone has fallen ill means that his body has deteriorated and his condition has changed. “I became afflicted with disease” means “I underwent change and deterioration.” Laylā al-Akhyaliyyah said:

“When al-Hajjāj descended upon an ailing land,
He traced its deepest malady and brought it healing.”

Another poet said:

“Have you not seen how the earth grew sick
At the loss of al-Husayn, and the lands shuddered?”

Disease revolves around four meanings: corruption, weakness, deficiency, and darkness. Thus, a man is said to have “ailed” in a matter when he showed weakness in it and did not exert himself fully. An eye with an “ailing gaze” has a languid, weak gaze. A wind, too, is described as “ailing” in its blowing, as in the verse:

“The winds came faintly to your dwelling places.”

That is, they were gentle and weak, so as not to erase the traces of those dwellings.

Ibn al-A‘rābī said: The basic meaning of disease is deficiency. Hence, a diseased body is one deficient in strength, and a diseased heart is one deficient in religion. To say that someone “ailed in attending to my need” means that his efforts slackened.

Al-Azharī reported from al-Mundhirī, from one of his companions: Disease is the darkening and disturbance of the natural constitution after its clarity. He said: Disease also means darkness. He cited the verse:

“A night that ailed on every side,
With neither sun nor moon to give it light.”

This is its basic linguistic meaning.