The word(s) "hearts" appears 136 time(s) in 127 verse(s) in Quran in Muhammad Habib Shakir translation.

(11) And hold fast by the covenant of Allah all together and be not disunited, and remember the favor of Allah on you when you were enemies, then He united your hearts so by His favor you became brethren; and you were on the brink of a pit of fire, then He saved you from it, thus does Allah make clear to you His communications that you may follow the right way.

(12) And Allah did not make it but as good news for you, and that your hearts might be at ease thereby, and victory is only from Allah, the Mighty, the Wise.

(13) We will cast terror into the hearts of those who disbelieve, because they set up with Allah that for which He has sent down no authority, and their abode is the fire, and evil is the abode of the unjust.

(14) Then after sorrow He sent down security upon you, a calm coming upon a party of you, and (there was) another party whom their own souls had rendered anxious; they entertained about Allah thoughts of ignorance quite unjustly, saying: We have no hand in the affair. Say: Surely the affair is wholly (in the hands) of Allah. They conceal within their souls what they would not reveal to you. They say: Had we any hand in the affair, we would not have been slain here. Say: Had you remained in your houses, those for whom slaughter was ordained would certainly have gone forth to the places where they would be slain, and that Allah might test what was in your breasts and that He might purge what was in your hearts; and Allah knows what is in the breasts.

(15) O you who believe! be not like those who disbelieve and say of their brethren when they travel in the earth or engage in fighting: Had they been with us, they would not have died and they would not have been slain; so Allah makes this to be an intense regret in their hearts; and Allah gives life and causes death and Allah sees what you do.

(16) And that He might know the hypocrites; and it was said to them: Come, fight in Allah's way, or defend yourselves. They said: If we knew fighting, we would certainly have followed you. They were on that day much nearer to unbelief than to belief. They say with their mouths what is not in their hearts, and Allah best knows what they conceal.

(17) These are they of whom Allah knows what is in their hearts; therefore turn aside from them and admonish them, and speak to them effectual words concerning themselves.

(18) But no! by your Lord! they do not believe (in reality) until they make you a judge of that which has become a matter of disagreement among them, and then do not find any straitness in their hearts as to what you have decided and submit with entire submission.

(19) Except those who reach a people between whom and you there is an alliance, or who come to you, their hearts shrinking from fighting you or fighting their own people; and if Allah had pleased, He would have given them power over you, so that they should have certainly fought you; therefore if they withdraw from you and do not fight you and offer you peace, then Allah has not given you a way against them.

(20) Therefore, for their breaking their covenant and their disbelief in the communications of Allah and their killing the prophets wrongfully and their saying: Our hearts are covered; nay! Allah set a seal upon them owing to their unbelief, so they shall not believe except a few.