The word(s) "lest" appears 66 time(s) in 65 verse(s) in Quran in Mohsin Khan translation.

(61) "And truly, I seek refuge with my Lord and your Lord, lest you should stone me (or call me a sorcerer or kill me).

(62) O you who believe! Raise not your voices above the voice of the Prophet (صلى الله عليه وسلم), nor speak aloud to him in talk as you speak aloud to one another, lest your deeds should be rendered fruitless while you perceive not.

(63) O you who believe! If a Fasiq (liar - evil person) comes to you with any news, verify it, lest you should harm people in ignorance, and afterwards you become regretful for what you have done.

(64) And We have left there a sign (i.e. the place of the Dead Sea in Palestine) for those who fear the painful torment.

(65) Has not the time come for the hearts of those who believe (in the Oneness of Allah - Islamic Monotheism) to be affected by Allah's Reminder (this Qur'an), and that which has been revealed of the truth, lest they become as those who received the Scripture [the Taurat (Torah) and the Injeel (Gospel)] before (i.e. Jews and Christians), and the term was prolonged for them and so their hearts were hardened? And many of them were Fasiqun (the rebellious, the disobedient to Allah).