It is accepted by Muslims that the Sallah is part of the religion. To what degree of importance is it? Is Sallah only for people who try to be good Muslims? Is it a basic for being Muslim? Can Sallah be trivialized? With as much flexibility as there is around performing the Sallah with concessions for different situations, is it appropriate for it to be skipped? In these times it can be said that we've seen and heard it all.
The messenger of ALLAH, peace be upon him, said that Islam is built upon five pillars, and Sallah is one of them. The word for pillar in Arabic is Rukun, and the famous "five pillars of Islam", are the Arkaan of Islam. In Shari'ah, a rukun is something that is essential for something to be, analogous to a structure that needs a certain number of pillars so that it will not collapse. Without all of the Rukun of Sallah, the sallah is not sallah, and is void and unaccepted, and must be repeated properly. The same applies to a rukun of Haj. So what about a missing Rukun of al-Islam? There is question about whether a person with no Sallah is Muslim. It is a classical topic and one which deserves to be addressed.