I had a small discussion with my friend Marc (here), and I thought of asking this in a separate question.
Notice that I am asking in context of Islam, as the definition of religion is broad.
In Quran, there is this verse (Quran 45:23):
Have you seen he who has taken as his god his [own] desire, and Allah has sent him astray due to knowledge and has set a seal upon his hearing and his heart and put over his vision a veil? So who will guide him after Allah ? Then will you not be reminded?
What I understood from it is that you don't need to have a God to be in a religion, and that even by not having God, you are still in the religion of desire. Where am I wrong?
Besides, is there any discussions or any verses that mention this topic?