The word(s) "forty" appears 4 time(s) in 4 verse(s) in Quran in Muhammad Habib Shakir translation.

(1) And when We appointed a time of forty nights with Musa, then you took the calf (for a god) after him and you were unjust.

(2) He said: So it shall surely be forbidden to them for forty years, they shall wander about in the land, therefore do not grieve for the nation of transgressors.

(3) And We appointed with Musa a time of thirty nights and completed them with ten (more), so the appointed time of his Lord was complete forty nights, and Musa said to his brother Haroun: Take my place among my people, and act well and do not follow the way of the mischief-makers.

(4) And We have enjoined on man doing of good to his parents; with trouble did his mother bear him and with trouble did she bring him forth; and the bearing of him and the weaning of him was thirty months; until when he attains his maturity and reaches forty years, he says: My Lord! grant me that I may give thanks for Thy favor which Thou hast bestowed on me and on my parents, and that I may do good which pleases Thee and do good to me in respect of my offspring; surely I turn to Thee, and surely I am of those who submit.