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

(41) And He has affixed into the earth mountains standing firm, lest it should shake with you; and rivers and roads, that you may guide yourselves.

(42) And fulfil the Covenant of Allah (Bai'ah: pledge for Islam) when you have covenanted, and break not the oaths after you have confirmed them - and indeed you have appointed Allah your surety. Verily! Allah knows what you do.

(43) And make not your oaths a means of deception among yourselves, lest a foot should slip after being firmly planted, and you may have to taste the evil (punishment in this world) of having hindered (men) from the Path of Allah (i.e. Belief in the Oneness of Allah and His Messenger, Muhammad صلى الله عليه و سلم), and yours will be a great torment (i.e. the Fire of Hell in the Hereafter).

(44) Say (O Muhammad صلى الله عليه و سلم) Ruh-ul-Qudus [Jibril (Gabriel)] has brought it (the Qur'an) down from your Lord with truth, that it may make firm and strengthen (the Faith of) those who believe, and as a guidance and glad tidings to those who have submitted (to Allah as Muslims).

(45) And had We not made you stand firm, you would nearly have inclined to them a little.

(46) And say (O Muhammad صلى الله عليه و سلم): My Lord! Let my entry (to the city of Al-Madinah) be good, and (likewise) my exit (from the city of Makkah) be good. And grant me from You an authority to help me (or a firm sign or a proof).

(47) And We made their hearts firm and strong (with the light of Faith in Allah and bestowed upon them patience to bear the separation of their kith and kin and dwellings) when they stood up and said: "Our Lord is the Lord of the heavens and the earth, never shall we call upon any ilah (god) other than Him; if we did, we should indeed have uttered an enormity in disbelief.

(48) And indeed We made a covenant with Adam before, but he forgot, and We found on his part no firm will-power.

(49) And We have placed on the earth firm mountains, lest it should shake with them, and We placed therein broad highways for them to pass through, that they may be guided.

(50) Is not He (better than your gods) Who has made the earth as a fixed abode, and has placed rivers in its midst, and has placed firm mountains therein, and has set a barrier between the two seas (of salt and sweet water)? Is there any ilah (god) with Allah? Nay, but most of them know not!