It is necessary to engage in some sort of mental work. Not engaging the brain causes increase in moisture in the brain, which causes dim-wittedness. On the other hand, over taxing the brain with deep thought, causes dryness to the brain which leads to weakness.

It is therefore preferable to estimate the amount of work prior to undertaking it. Be in the habit of reading and teaching. Recite the Qur'ân daily. Try and read some book or the other. Always think over matters. Do not become so angry that you lose control over yourself. At the same time do not be so tolerant that you are unable to maintain any discipline.