The word(s) "fast" appears 42 time(s) in 39 verse(s) in Quran in Abdullah Yusuf Ali translation.

(11) When Talut set forth with the armies, he said: "Allah will test you at the stream: if any drinks of its water, He goes not with my army: Only those who taste not of it go with me: A mere sip out of the hand is excused." but they all drank of it, except a few. When they crossed the river,- He and the faithful ones with him,- they said: "This day We cannot cope with Goliath and his forces." but those who were convinced that they must meet Allah, said: "How oft, by Allah's will, Hath a small force vanquished a big one? Allah is with those who steadfastly persevere."

(12) And hold fast, all together, by the rope which Allah (stretches out for you), and be not divided among yourselves; and remember with gratitude Allah's favour on you; for ye were enemies and He joined your hearts in love, so that by His Grace, ye became brethren; and ye were on the brink of the pit of Fire, and He saved you from it. Thus doth Allah make His Signs clear to you: That ye may be guided.

(13) Did ye think that ye would enter Heaven without Allah testing those of you who fought hard (In His Cause) and remained steadfast?

(14) How many of the prophets fought (in Allah's way), and with them (fought) Large bands of godly men? but they never lost heart if they met with disaster in Allah's way, nor did they weaken (in will) nor give in. And Allah Loves those who are firm and steadfast.

(15) Never should a believer kill a believer; but (If it so happens) by mistake, (Compensation is due): If one (so) kills a believer, it is ordained that he should free a believing slave, and pay compensation to the deceased's family, unless they remit it freely. If the deceased belonged to a people at war with you, and he was a believer, the freeing of a believing slave (Is enough). If he belonged to a people with whom ye have treaty of Mutual alliance, compensation should be paid to his family, and a believing slave be freed. For those who find this beyond their means, (is prescribed) a fast for two months running: by way of repentance to Allah: for Allah hath all knowledge and all wisdom.

(16) Except for those who repent, mend (their lives) hold fast to Allah, and purify their religion as in Allah's sight: if so they will be (numbered) with the believers. And soon will Allah grant to the believers a reward of immense value.

(17) Then those who believe in Allah, and hold fast to Him,- soon will He admit them to mercy and grace from Himself, and guide them to Himself by a straight way.

(18) If only they had stood fast by the Law, the Gospel, and all the revelation that was sent to them from their Lord, they would have enjoyed happiness from every side. There is from among them a party on the right course: but many of them follow a course that is evil.

(19) Say: "O People of the Book! ye have no ground to stand upon unless ye stand fast by the Law, the Gospel, and all the revelation that has come to you from your Lord." It is the revelation that cometh to thee from thy Lord, that increaseth in most of them their obstinate rebellion and blasphemy. But sorrow thou not over (these) people without Faith.

(20) Allah will not call you to account for what is futile in your oaths, but He will call you to account for your deliberate oaths: for expiation, feed ten indigent persons, on a scale of the average for the food of your families; or clothe them; or give a slave his freedom. If that is beyond your means, fast for three days. That is the expiation for the oaths ye have sworn. But keep to your oaths. Thus doth Allah make clear to you His signs, that ye may be grateful.