The word(s) "let" appears 245 time(s) in 205 verse(s) in Quran in Abdullah Yusuf Ali translation.

(71) O ye who believe! fight the unbelievers who gird you about, and let them find firmness in you: and know that Allah is with those who fear Him.

(72) He it is Who enableth you to traverse through land and sea; so that ye even board ships;- they sail with them with a favourable wind, and they rejoice thereat; then comes a stormy wind and the waves come to them from all sides, and they think they are being overwhelmed: they cry unto Allah, sincerely offering (their) duty unto Him saying, "If thou dost deliver us from this, we shall truly show our gratitude!"

(73) Say: "I have no power over any harm or profit to myself except as Allah willeth. To every people is a term appointed: when their term is reached, not an hour can they cause delay, nor (an hour) can they advance (it in anticipation)."

(74) Say: "In the bounty of Allah. And in His Mercy,- in that let them rejoice": that is better than the (wealth) they hoard.

(75) let not their speech grieve thee: for all power and honour belong to Allah: It is He Who heareth and knoweth (all things).

(76) If We delay the penalty for them for a definite term, they are sure to say, "What keeps it back?" Ah! On the day it (actually) reaches them, nothing will turn it away from them, and they will be completely encircled by that which they used to mock at!

(77) Perchance thou mayest (feel the inclination) to give up a part of what is revealed unto thee, and thy heart feeleth straitened lest they say, "Why is not a treasure sent down unto him, or why does not an angel come down with him?" But thou art there only to warn! It is Allah that arrangeth all affairs!

(78) "If then they (your false gods) answer not your (call), know ye that this revelation is sent down (replete) with the knowledge of Allah, and that there is no god but He! will ye even then submit (to Islam)?"

(79) "Of no profit will be my counsel to you, much as I desire to give you (good) counsel, if it be that Allah willeth to leave you astray: He is your Lord! and to Him will ye return!"

(80) (The Messengers) said: "O Lut! We are Messengers from thy Lord! By no means shall they reach thee! now travel with thy family while yet a part of the night remains, and let not any of you look back: but thy wife (will remain behind): To her will happen what happens to the people. Morning is their time appointed: Is not the morning nigh?"