I have grown up hearing that Christianity is not a religion but a relationship. I get it. But Christianity is a religion. By simply calling it a relationship those who do so are opting out of categorization and evaluation, as in Christianity is so superior to religions that it can’t be classified as a religion. There is a touch of arrogance and triumphalism here that I resist. “My faith is so far above your religion that you have no right to evaluate it as a religion.”
1 Timothy 3:16 is usually translated this way. “Great indeed, we confess, is the mystery of godliness.” The word “godliness” can also be translated religion, depending on the context. The CEV and the GNB translate it as religion. This is the most natural sense, in my opinion. The Apostle Paul calls the Christian faith a religion.
Luke Norsworthy has posted at JesusCreed on this. It is worth the read.