The word(s) "firmness" appears 5 time(s) in 5 verse(s) in Quran in Muhammad Habib Shakir translation.

(1) And when We took a promise from you and lifted the mountain over you: Take hold of the law (Tavrat) We have given you with firmness and bear in mind what is in it, so that you may guard (against evil).

(2) And when We made a covenant with you and raised the mountain over you: Take hold of what We have given you with firmness and be obedient. They said: We hear and disobey. And they were made to imbibe (the love of) the calf into their hearts on account of their unbelief. Say: Evil is that which your belief bids you if you are believers.

(3) And We ordained for him in the tablets admonition of every kind and clear explanation of all things; so take hold of them with firmness and enjoin your people to take hold of what is best thereof; I will show you the abode of the transgressors.

(4) And when We shook the mountain over them as if it were a covering overhead, and they thought that it was going to fall down upon them: Take hold of what We have given you with firmness, and be mindful of what is in it, so that you may guard (against evil).

(5) What! is it a wonder to the people that We revealed to a man from among themselves, saying: Warn the people and give good news to those who believe that theirs is a footing of firmness with their Lord. The unbelievers say: This is most surely a manifest enchanter.