Surah 9. Al-Tawba, Ayah 28

The term najas ("impure") occurs in the Qur'an only in this one instance, and carries an exclusively spiritual meaning (see Manar X, 322ff.). To this day, the bedouin of Central and Eastern Arabia - who, contrary to the modern town-dwellers, have preserved the purity of the Arabic idiom to a high degree - describe a person who is immoral, faithless or wicked as najas. "The Inviolable House of Worship" (al-masjid al-haram) is, of course, the Ka'bah and, by implication, the whole of the territory of Mecca: which explains the next sentence.

Lit., "after this their year" - i.e., after the year 9 H., in which this surah was revealed.

This is an allusion to the apprehension on the part of some Muslims (and not only at the time of the revelation of this verse) that an exclusion of unbelievers from living in or visiting Mecca might lead to a loss of its position as a centre of trade and commerce, and thus to an impoverishment of its inhabitants.

 i.e., impure spiritually because of idolatry, not physically.

 The 9 th  year of the Prophet’s migration from Mecca to Medina.

Unclean: because Muslims are enjoined to be strict in cleanliness, as well as in purity of mind and heart, so that their word can be relied upon.

The concourse in Makkah added to the profits of trade and commerce. "But fear not," we are told: "the Pagans are a waning power, bound to disappear, and you should strengthen your own community, that they may more than counter-balance the apparent loss of custom; and Allah has other means of improving your economic position." This actually happened. The Pagans were extinguished from Arabia, and the concourse of pilgrims from all parts of the world increased the numbers more than a hundred-fold. Here is commonsense, wisdom, and statesmanship, even if we look at it from a purely human point of view.

This year of theirs: there is a two-fold meaning: (1) now that you have complete control of Makkah and are, charged with the purity of worship there, shut out all impurity from this year: (2) you have seen how the Pagans have behaved this year; their year of power and misuse of that power may be called their year; it is over, and now you Muslims are responsible.