Ruling on Hanging Supplication in Cars

Question: We have seen some people who hang papers containing [supplication] in their cars and on their doors like the supplication of leaving the house and expiation of assembly; and these are supplications that have been reported from Allah’s Messenger (sallallaahu alayhi wa sallam). How correct is that?

Response: I do not know of any harm in that because it entails reminder to the people, since most of them have not memorized these invocations. So if you write it and place it in front of them, it becomes easy for them to read it. For instance, there is no problem if a person writes the invocation for the expiation of assembly in his study circle in order to remind those who are sitting to invoke Allaah with it whenever they get up. Similarly, there is nothing wrong with the small placard that is hung in front of passengers in cars containing the supplication of travelling.

Source: Fataawaa Mu’aasirah by Shaykh Muhammad Saalih al-Uthaymeen p. 478- 479