Appears 9 times in the Quran. (Root: ربع)
  1. Those who swear that they will not go in to their wives should wait four months; so if they go back, then Allah is surely Forgiving, Merciful.

  2. And (as for) those of you who die and leave wives behind, they should keep themselves in waiting for four months and ten days; then when they have fully attained their term, there is no blame on you for what they do for themselves in a lawful manner; and Allah is aware of what you do.

  3. And when Ibrahim said: My Lord! show me how Thou givest life to the dead, He said: What! and do you not believe? He said: Yes, but that my heart may be at ease. He said: Then take four of the birds, then train them to follow you, then place on every mountain a part of them, then call them, they will come to you flying; and know that Allah is Mighty, Wise.

  4. And as for those who are guilty of an indecency from among your women, call to witnesses against them four (witnesses) from among you; then if they bear witness confine them to the houses until death takes them away or Allah opens some way for them.

  5. So go about in the land for four months and know that you cannot weaken Allah and that Allah will bring disgrace to the unbelievers.

  6. Surely the number of months with Allah is twelve months in Allah's ordinance since the day when He created the heavens and the earth, of these four being sacred; that is the right reckoning; therefore be not unjust to yourselves regarding them, and fight the polytheists all together as they fight you all together; and know that Allah is with those who guard (against evil).

  7. And those who accuse free women then do not bring four witnesses, flog them, (giving) eighty stripes, and do not admit any evidence from them ever; and these it is that are the transgressors,

  8. Why did they not bring four witnesses of it? But as they have not brought witnesses they are liars before Allah.

  9. And He made in it mountains above its surface, and He blessed therein and made therein its foods, in four periods: alike for the seekers.