The word(s) "hearts" appears 159 time(s) in 147 verse(s) in Quran in Abdullah Yusuf Ali translation.

(1) And who believe in the Revelation sent to thee, and sent before thy time, and (in their hearts) have the assurance of the Hereafter.

(2) Allah hath set a seal on their hearts and on their hearing, and on their eyes is a veil; great is the penalty they (incur).

(3) In their hearts is a disease; and Allah has increased their disease: And grievous is the penalty they (incur), because they are false (to themselves).

(4) Thenceforth were your hearts hardened: They became like a rock and even worse in hardness. For among rocks there are some from which rivers gush forth; others there are which when split asunder send forth water; and others which sink for fear of Allah. And Allah is not unmindful of what ye do.

(5) They say, "Our hearts are the wrappings (which preserve Allah's Word: we need no more)." Nay, Allah's curse is on them for their blasphemy: Little is it they believe.

(6) And remember We took your covenant and We raised above you (the towering height) of Mount (Sinai): (Saying): "Hold firmly to what We have given you, and hearken (to the Law)": They said:" We hear, and we disobey:" And they had to drink into their hearts (of the taint) of the calf because of their Faithlessness. Say: "Vile indeed are the behests of your Faith if ye have any faith!"

(7) Say those without knowledge: "Why speaketh not Allah unto us? or why cometh not unto us a Sign?" So said the people before them words of similar import. Their hearts are alike. We have indeed made clear the Signs unto any people who hold firmly to Faith (in their hearts).

(8) Allah will not call you to account for thoughtlessness in your oaths, but for the intention in your hearts; and He is Oft-forgiving, Most Forbearing.

(9) There is no blame on you if ye make an offer of betrothal or hold it in your hearts. Allah knows that ye cherish them in your hearts: But do not make a secret contract with them except in terms Honourable, nor resolve on the tie of marriage till the term prescribed is fulfilled. And know that Allah Knoweth what is in your hearts, and take heed of Him; and know that Allah is Oft-forgiving, Most Forbearing.

(10) He it is Who has sent down to thee the Book: In it are verses basic or fundamental (of established meaning); they are the foundation of the Book: others are allegorical. But those in whose hearts is perversity follow the part thereof that is allegorical, seeking discord, and searching for its hidden meanings, but no one knows its hidden meanings except Allah. And those who are firmly grounded in knowledge say: "We believe in the Book; the whole of it is from our Lord:" and none will grasp the Message except men of understanding.