The word(s) "soft" appears 3 time(s) in 3 verse(s) in Quran in Abdullah Yusuf Ali translation.

(1) It is Allah Who made your habitations homes of rest and quiet for you; and made for you, out of the skins of animals, (tents for) dwellings, which ye find so light (and handy) when ye travel and when ye stop (in your travels); and out of their wool, and their soft fibres (between wool and hair), and their hair, rich stuff and articles of convenience (to serve you) for a time.

(2) We bestowed Grace aforetime on David from ourselves: "O ye Mountains! Sing ye back the Praises of Allah with him! and ye birds (also)! And We made the iron soft for him;-

(3) Allah has revealed (from time to time) the most beautiful Message in the form of a Book, consistent with itself, (yet) repeating (its teaching in various aspects): the skins of those who fear their Lord tremble thereat; then their skins and their hearts do soften to the celebration of Allah's praises. Such is the guidance of Allah: He guides therewith whom He pleases, but such as Allah leaves to stray, can have none to guide.