The word(s) "spontaneously" appears 2 time(s) in 2 verse(s) in Quran in Muhammad Habib Shakir translation.

(1) Surely the Safa and the Marwa are among the signs appointed by Allah; so whoever makes a pilgrimage to the House or pays a visit (to it), there is no blame on him if he goes round them both; and whoever does good spontaneously, then surely Allah is Grateful, Knowing.

(2) For a certain number of days; but whoever among you is sick or on a journey, then (he shall fast) a (like) number of other days; and those who are not able to do it may effect a redemption by feeding a poor man; so whoever does good spontaneously it is better for him; and that you fast is better for you if you know.