The word(s) "steadfastly" appears 2 time(s) in 2 verse(s) in Quran in Abdullah Yusuf Ali translation.

(1) When Talut set forth with the armies, he said: "Allah will test you at the stream: if any drinks of its water, He goes not with my army: Only those who taste not of it go with me: A mere sip out of the hand is excused." but they all drank of it, except a few. When they crossed the river,- He and the faithful ones with him,- they said: "This day We cannot cope with Goliath and his forces." but those who were convinced that they must meet Allah, said: "How oft, by Allah's will, Hath a small force vanquished a big one? Allah is with those who steadfastly persevere."

(2) But those who had been granted (true) knowledge said: "Alas for you! The reward of Allah (in the Hereafter) is best for those who believe and work righteousness: but this none shall attain, save those who steadfastly persevere (in good)."