The word(s) "firm" appears 74 time(s) in 72 verse(s) in Quran in Mohsin Khan translation.

(31) O you who believe! When you meet (an enemy) force, take a firm stand against them and remember the Name of Allah much (both with tongue and mind), so that you may be successful.

(32) And this Qur'an is not such as could ever be produced by other than Allah (Lord of the heavens and the earth), but it is a confirmation of (the revelation) which was before it [i.e. the Taurat (Torah), and the Injeel (Gospel)], and a full explanation of the Book (i.e. laws, decreed for mankind) - wherein there is no doubt - from the Lord of the 'Alamin (mankind, jinn, and all that exists).

(33) So stand (ask Allah to make) you (Muhammad صلى الله عليه و سلم) firm and straight (on the religion of Islamic Monotheism) as you are commanded and those (your companions) who turn in repentance (unto Allah) with you, and transgress not (Allah's Legal Limits). Verily, He is All-Seer of what you do.

(34) And all that We relate to you (O Muhammad صلى الله عليه و سلم) of the news of the Messengers is in order that We may make strong and firm your heart thereby. And in this (chapter of the Qur'an) has come to you the truth, as well as an admonition and a reminder for the believers.

(35) Indeed in their stories, there is a lesson for men of understanding. It (the Qur'an) is not a forged statement but a confirmation of (Allah's existing Books) which were before it [i.e. the Taurat (Torah), the Injeel (Gospel) and other Scriptures of Allah] and a detailed explanation of everything and a guide and a Mercy for the people who believe.

(36) And it is He Who spread out the earth, and placed therein firm mountains and rivers and of every kind of fruits He made Zawjain Ithnain (two in pairs - may mean two kinds or it may mean: of two varieties, e.g. black and white, sweet and sour, small and big). He brings the night as a cover over the day. Verily, in these things, there are Ayat (proofs, evidence, lessons, signs, etc.) for people who reflect.

(37) Allah blots out what He wills and confirms (what He wills). And with Him is the Mother of the Book (Al-Lauh Al-Mahfuz)

(38) See you not how Allah sets forth a parable? A goodly word as a goodly tree, whose root is firmly fixed, and its branches (reach) to the sky (i.e. very high).

(39) Allah will keep firm those who believe, with the word that stands firm in this world (i.e. they will keep on worshipping Allah Alone and none else), and in the Hereafter. And Allah will cause to go astray those who are Zalimun (polytheists and wrong-doers), and Allah does what He wills.

(40) And the earth We have spread out, and have placed therein firm mountains, and caused to grow therein all kinds of things in due proportion.