Are the mentioned conditions for Bid‘ah (innovation in religion) established, namely: that it be an act of worship, that the Prophet (peace be upon him) needed it but did not do it, and that there was no impediment preventing him from doing it, and upon these conditions are all issues built? And how is the issue of hanging up plaques of post-prayer remembrances in mosques addressed based on these conditions?

Innovation (Bid'ah) is every newly introduced matter in religion that the Prophet, peace and blessings be upon him, and his companions did not do, and that does not fall under a legitimate (Shar'i) principle. Among its criteria is that every matter which the Prophet, peace and blessings be upon him, and his companions abstained from, despite the presence of a motivating factor for it and the absence of any impediment to performing it, then performing it now is an innovation. However, if the Prophet, peace and blessings be upon him, abstained from something due to the absence of a motivating factor or the presence of an impediment, then performing it now is not considered an innovation. Examples of this include the compilation of the Qur'an and performing Tarawih prayer in congregation.