Why Do We Say Salam In Front Of Prophet Muhammad (sws) Grave ?
There are two important points in this regard: 1 ) The compulsion of saying Durud on Prophet Muhammad (sws) whenever his name is invoked : As far as this compulsion is concerned, this can be understood in the light of Quran 33:56 and the verses after that which makes it clear why Muslims were asked to increase their prayers and supplications for the Prophet (Sws) i.e. to counter the schemes of hypocrites of Medina. That is why we find certain hadith narratives which apparently give harsh warnings to the ones who do not send Durud on Prophet (sws) whenever his name is invoked, they were for this specific time in a specific situation when hypocrites of Medina were plotting against the Prophet (sws) and His family. This point has been explained in detail in the videos provided in the following thread : Discussion 51672 2 ) Saying of Durud in general , whether at his grave or far away : The directive given in Quran 33:56 had a very specific context indeed, but we see that Quran is very sensitive when it comes to respect for Prophet Muhammad (sws) (e.g. see: Quran 49:1-5 AND Quran 4:65, Quran 24:63 ) and the matter of respect is something which cannot be disregarded even after death of Prophet Muhammad (SwS). And in additon to logic, we humans also possess a psychological and emotional side to us. This Durud is not required by the Prophet (SWS), instead, it is also required both by our human side and our religious side to fulfil our need to express our love, respect and gratitude for the Prophet (SWS). And what better and pious way to express these emotions than by sending prayers for Him. This is why Muslims send their prayers for Prophet Muhammad (sws) whether they are visiting His grave (sws) or when they are away, in general and during their Salah. The matter gets more emotional when a person visits the grave of Prophet Muhammad (sws) because of the same human side to us, that is why scholars have tried to lay out certain boundaries so that we humans do not transgress our bounds when feeling emotional during such visits. That is the very reason, Prophet Muhammad (sws) asked Muslims to not make His grave a place of festivity and can send their prayers to him from wherever they are and those prayers would reach him. This was actually said with the intention of stopping people from any form of transgression when it comes to the personality of Prophet Muhammad (Sws). There is no such compulsion in religion to visit grave of Prophet Muhammad (sws) to make dua for him, instead it appears that Prophet Muhammad (sws) actually discouraged Muslims from visiting his grave repeatedly . See the following narration , for instance: https://hadeethenc.com/en/browse/hadith/3346 Now as far as other ahadith are concerned where it is mentioned that our prayers will be presented to Prophet Muhammad (sws), then this is quite a possibility that Prophet can be informed of the prayers his ummah sends for him. If Allah can make special arrangments for people who die in his cause (‘ shaheed ‘) ( Quran 3:169 ) then why cannot this specific arrangment be made for Prophet Muhammad (Sws) wherever Allah has kept his pure soul. There are a lot of Ahadith on this topic and it is not possible to comment on each of them but the above discussion and the following videos will be helpful to some extent as to what principles should be kept in mind when studying those ahadith: https://youtu.be/mOgaa5y9DCs