The word(s) "four" appears 18 time(s) in 17 verse(s) in Quran in Muhammad Habib Shakir translation.

(11) And (as for) those who accuse their wives and have no witnesses except themselves, the evidence of one of these (should be taken) four times, bearing Allah to witness that he is most surely of the truthful ones.

(12) And it shall avert the chastisement from her if she testify four times, bearing Allah to witness that he is most surely one of the liars;

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

(14) And Allah has created from water every living creature: so of them is that which walks upon its belly, and of them is that which walks upon two feet, and of them is that which walks upon four; Allah creates what He pleases; surely Allah has power over all things.

(15) All praise is due to Allah, the Originator of the heavens and the earth, the Maker of the angels, apostles flying on wings, two, and three, and four; He increases in creation what He pleases; surely Allah has power over all things.

(16) 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.

(17) Do you not see that Allah knows whatever is in the heavens and whatever is in the earth? Nowhere is there a secret counsel between three persons but He is the fourth of them, nor (between) five but He is the sixth of them, nor less than that nor more but He is with them wheresoever they are; then He will inform them of what they did on the day of resurrection: surely Allah is Cognizant of all things.