The word(s) "guard" appears 80 time(s) in 76 verse(s) in Quran in Abdullah Yusuf Ali translation.

(21) And this is a Book which We have sent down, bringing blessings, and confirming (the revelations) which came before it: that thou mayest warn the mother of cities and all around her. Those who believe in the Hereafter believe in this (Book), and they are constant in guarding their prayers.

(22) Say: "Bring forward your witnesses to prove that Allah did forbid so and so." If they bring such witnesses, be not thou amongst them: Nor follow thou the vain desires of such as treat our signs as falsehoods, and such as believe not in the Hereafter: for they hold others as equal with their guardian-Lord.

(23) Your guardian-Lord is Allah, Who created the heavens and the earth in six days, and is firmly established on the throne (of authority): He draweth the night as a veil o'er the day, each seeking the other in rapid succession: He created the sun, the moon, and the stars, (all) governed by laws under His command. Is it not His to create and to govern? Blessed be Allah, the Cherisher and Sustainer of the worlds!

(24) But what plea have they that Allah should not punish them, when they keep out (men) from the sacred Mosque - and they are not its guardians? No men can be its guardians except the righteous; but most of them do not understand.

(25) The vanguard (of Islam)- the first of those who forsook (their homes) and of those who gave them aid, and (also) those who follow them in (all) good deeds,- well-pleased is Allah with them, as are they with Him: for them hath He prepared gardens under which rivers flow, to dwell therein for ever: that is the supreme felicity.

(26) Nor should the Believers all go forth together: if a contingent from every expedition remained behind, they could devote themselves to studies in religion, and admonish the people when they return to them,- that thus they (may learn) to guard themselves (against evil).

(27) Those who believe and (constantly) guard against evil;-

(28) "Then will come after that (period) seven dreadful (years), which will devour what ye shall have laid by in advance for them,- (all) except a little which ye shall have (specially) guarded.

(29) (Joseph) said: "Set me over the store-houses of the land: I will indeed guard them, as one that knows (their importance)."

(30) (Jacob) said: "Never will I send him with you until ye swear a solemn oath to me, in Allah's name, that ye will be sure to bring him back to me unless ye are yourselves hemmed in (and made powerless). And when they had sworn their solemn oath, he said: "Over all that we say, be Allah the witness and guardian!"