Shaykh Abd al-Aziz bin Baz (rahimahullaah) was asked:
Question: Some people place Qur'anic verses and Prophetic statements in rooms in [their] residences, or restaurants or offices. Likewise in the hospitals and clinics they hang the saying of Allaah, the Exalted, "And when I am ill He is the one who cures me" (26:80) and other (verses).
Is hanging those (verses and statements) considered to be amongst the talismans which are prohibited in the Shariah, with the knowledge that their intent is to receive blessings and repel the devils, and sometimes the intent could also be to remind the forgetful and notify the heedless. And is placing the qur'an (mushaf) with the justification of seeking blessings also considered to be from the talismans.
The Shaykh's answer:
Answer: When the intent behind what the questioner has mentioned is to remind the people, to teach them and to benefit them, there is no harm in that. As for when the intent is to consider [the placing and hanging of these words] to be a protection from the devils or the jinn, then I do not know of any basis for this. Likewise, placing the qur'an (mushaf) in the car for blessing through that, this does not have any basis and it is not legislated. As for when he places it in the car in order to read it at certain times, or so that some of the passengers read it, then this is good and there is no harm in it. And Allaah is the overseer of success. al-Bida' wal-Muhdathaat wa Maa Laa Asla Lahaa (p. 259-260).