The word(s) "forthwith" appears 4 time(s) in 4 verse(s) in Quran in Abdullah Yusuf Ali translation.

(1) forthwith he (starts) constructing the Ark: Every time that the chiefs of his people passed by him, they threw ridicule on him. He said: "If ye ridicule us now, we (in our turn) can look down on you with ridicule likewise!

(2) Then when the bearer of the good news came, He cast (the shirt) over his face, and he forthwith regained clear sight. He said: "Did I not say to you, 'I know from Allah that which ye know not?'"

(3) Seest thou not that Allah sends down rain from the sky, and forthwith the earth becomes clothed with green? for Allah is He Who understands the finest mysteries, and is well-acquainted (with them).

(4) And penetrate forthwith into the midst (of the foe) en masse;-