Could you provide a few examples of untrue Christianity?
Jim Jones and his gang.
There’s al. Kinds of faux “christians” out there- if you aren’t aware of that by now, I don’t know what to tell you. The internet has ample evidence of it readily available.
Any text book of Church history will give you dozens of examples from just the first 3 centuries. Modalism, Arianism, Sabellianism, Gnosticism, Pelagianism, Marcionism just to name a few. John, Peter, Paul and Jesus himself warned us of false teachers.
From the lips of the Lord, “Not everyone who says onto me, ‘Lord, Lord,’ will enter the kingdom of heaven.”
False prophets
Wolves [Christians, by all appearances] in sheeps’ [actual Christians] clothing
5 virgins [Christians] shut out of heaven
one talent servant [Christian] gets to gnash his teeth
the goats [Christians] get to gnash their teeth