Itikaf is the Islamic practice of staying in the mosque for a certain number of days, devoting oneself to worship, and staying away from worldly affairs.

One kind of itikaf is that which is practised in the mosque during the month of Ramadan. This is mentioned in the Quran in the second chapter (2:187). The second kind of itikaf is what may be called intellectual seclusion.

According to a number of traditions, the Prophet of Islam used to reflect most of the time. This is what is meant by intellectual seclusion, that is, deep thinking in silence.

Itikaf of the mosque is of a limited period. On the contrary, intellectual seclusion is unlimited. The companions of the Prophet used to engage in intellectual seclusion. (Shama’il  al-Tirmidhi, Hadith No. 225) Some examples have been mentioned in Islamic literature. For instance, after the death of Abu ad Darda Ansari, someone asked his wife what special worship her husband engaged in. His wife, Ummud Darda, replied: Attafakkur wal itibar. That is, thinking and taking lessons. (Hilyat al-Awliya, vol. 1, p. 208)

This intellectual seclusion is referred to in the Quran by these words: Tafakkur, tadabbur, tazakkur, tawassum, taaqqul, etc. All these words mean thinking deeply on everything. This action of thinking is extremely important. It is by thinking that all noble qualities are produced, for instance, wisdom, realization, intellectual development, increase of faith, discovery of deeper meaning, etc.

This intellectual seclusion is extremely important for a believer, but there is one necessary condition for it, and that is to save oneself from all kinds of distractions. Without this, intellectual seclusion is just not possible. The truth is that, intellectual seclusion is another name for continuous intellectual activity. By this intellectual activity, we achieve what is called in the Quran, an increase of faith. (The Quran, 8:2) If there is no intellectual activity, there is no increase in faith.