Al-Albaani: The reality is that the case with every beginner student of knowledge, and I was like that and probably still am, I used to read this hadith and it would be problematic, because in some narrations [there occurs], “There is nothing between a man and disbelief except abandoning the prayer. So whoever abandons the prayer has disbelieved,” and in some narrations, “… then he has committed shirk.”
Al-Albaani: I used to ask how can he have committed shirk? Yaa akhi, this person who has left praying, especially the one who does so out of laziness, how has he committed shirk?
I used to think that maybe there was a mistake on behalf of the narrator [of the hadith], I was a student of knowledge, then later our Lord granted me success in understanding, even if it was when I was older alhamdulillaah, [he granted me success in understanding it] such that I recognized that legislatively, as opposed to linguistically, there is no difference between kufr and shirk.
So all kufr is shirk and all shirk is kufr there is no difference between them legislatively, linguistically there is, because in the language kufr means to cover. Shirk is to make something a partner of another, like the polytheists who make equals with Allaah.
But later I came to recognise that every unbeliever, even if he wasn’t a polytheist linguistically, he was in reality. No unbeliever is free from being anything but a polytheist [mushrik], our Lord said, “Have you seen he who has taken as his god his [own] desire?” [Jaathiyah 45:23] He took as his god his own desires, so, everyone who follows his desires has made it a partner with Allaah, thus, any kufr–[for example] if someone were to reject a letter from the Noble Quraan it would mean that he has put his intellect in charge and has taken it as a god and it is from this angle that the shirk has come.
So, the one who said that all disbelief is polytheism and all polytheism is disbelief spoke truthfully, not like the one who says that not all kufr is shirk like you heard from at-Tahawi.
In reality this is knowledge which is very rare and is something through which many, many problems are resolved, from them being the verse, “Indeed, Allaah does not forgive association with Him, but He forgives what is less than that for whom He wills.” [Nisaa 4:48]
I read [a mention of] a problem about this verse in the Al-Manaar magazine which Sayyid Rashid Rida used to publish. An objection came his way which stated that the meaning of the aayah is that these unbelieving Europeans who believe in ‘nature’, they call it nature, i.e., that this universe has a creator and who do not know any more than that, it is possible that Allaah will forgive them because they are not polytheists. And so Sayyid Rashid Rida at that time was not able to give an answer like this one which if he had known then would have been the sound judgement [about this topic], [i.e., that] all kufr is shirk and all shirk is kufr.
Al-Hudaa wan-Noor, 341.