The word(s) "seal" appears 17 time(s) in 17 verse(s) in Quran in Mohsin Khan translation.

(1) Allah has set a seal on their hearts and on their hearing, (i.e. they are closed from accepting Allah's Guidance), and on their eyes there is a covering. Theirs will be a great torment.

(2) Because of their breaking the covenant, and of their rejecting the Ayat (proofs, evidence, verses, lessons, signs, revelations, etc.) of Allah, and of their killing the Prophets unjustly, and of their saying: "Our hearts are wrapped (with coverings, i.e. we do not understand what the Messengers say)" - nay, Allah has set a seal upon their hearts because of their disbelief, so they believe not but a little.

(3) Say (to the disbelievers): "Tell me, if Allah took away your hearing and your sight, and sealed up your hearts, who is there - an ilah (a god) other than Allah who could restore them to you?" See how variously We explain the Ayat (proofs, evidence, verses, lessons, signs, revelations, etc.), yet they turn aside.

(4) Is it not clear to those who inherit the earth in succession from its (previous) possessors, that had We willed, We would have punished them for their sins. And We seal up their hearts so that they hear not?

(5) Those were the towns whose story We relate unto you (O Muhammad صلى الله عليه وسلم). And there came indeed to them their Messengers with clear proofs, but they were not such as to believe in that which they had rejected before. Thus Allah does seal up the hearts of the disbelievers (from every kind of religious guidance).

(6) They are content to be with those (the women) who sit behind (at home). Their hearts are sealed up (from all kinds of goodness and right guidance), so they understand not.

(7) The ground (of complaint) is only against those who are rich, and yet ask exemption. They are content to be with (the women) who sit behind (at home) and Allah has sealed up their hearts (from all kinds of goodness and right guidance) so that they know not (what they are losing).

(8) Then after him We sent Messengers to their people. They brought them clear proofs, but they would not believe what they had already rejected beforehand. Thus We seal the hearts of the transgressors (those who disbelieve in the Oneness of Allah and disobey Him).

(9) They are those upon whose hearts, hearing (ears) and sight (eyes) Allah has set a seal. And they are the heedless!

(10) Thus does Allah seal up the hearts of those who know not [the proofs and evidence of the Oneness of Allah i.e. those who try not to understand true facts that which you (Muhammad صلى الله عليه وسلم) have brought to them].