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

(31) In the case of those who say, "Our Lord is Allah", and, further, stand straight and steadfast, the angels descend on them (from time to time): "Fear ye not!" (they suggest), "Nor grieve! but receive the Glad Tidings of the Garden (of Bliss), the which ye were promised!

(32) The same religion has He established for you as that which He enjoined on Noah - the which We have sent by inspiration to thee - and that which We enjoined on Abraham, Moses, and Jesus: Namely, that ye should remain steadfast in religion, and make no divisions therein: to those who worship other things than Allah, hard is the (way) to which thou callest them. Allah chooses to Himself those whom He pleases, and guides to Himself those who turn (to Him).

(33) Now then, for that (reason), call (them to the Faith), and stand steadfast as thou art commanded, nor follow thou their vain desires; but say: "I believe in the Book which Allah has sent down; and I am commanded to judge justly between you. Allah is our Lord and your Lord: for us (is the responsibility for) our deeds, and for you for your deeds. There is no contention between us and you. Allah will bring us together, and to Him is (our) Final Goal.

(34) What! have We given them a Book before this, to which they are holding fast?

(35) So hold thou fast to the Revelation sent down to thee; verily thou art on a Straight Way.

(36) For Allah is He Who gives (all) Sustenance,- Lord of Power,- Steadfast (for ever).

(37) And if any has not (the wherewithal), he should fast for two months consecutively before they touch each other. But if any is unable to do so, he should feed sixty indigent ones, this, that ye may show your faith in Allah and His Messenger. Those are limits (set by) Allah. For those who reject (Him), there is a grievous Penalty.

(38) It may be, if he divorced you (all), that Allah will give him in exchange consorts better than you,- who submit (their wills), who believe, who are devout, who turn to Allah in repentance, who worship (in humility), who travel (for Faith) and fast,- previously married or virgins.

(39) Those who remain steadfast to their prayer;