Download a copy of “The Definition of Christianity” by John Lennox and David Gooding (no strings attached, no email required) from Myrtlefield House Publishers. They have a number of other free resources available too.
Christianity is not essentially a system of morality (as is Confucianism) that has to be adapted to the changing fashion of the centuries or else become outmoded. Nor is it a system of abstract universal philosophical truths, the validity of which is independent of the thinkers who first perceived them. Nor is it like many a pagan religion was, a system of rituals which depended for their effectiveness on being performed correctly.