If you take the ruling ideology seriously you are one step from being a dissident.
- Slavoj Zizek
To paraphrase, if you take Christianity seriously you are one step from being a heretic.
To be somewhat playful, for Zizek, this entails living in the realm forged by a crucified revolutionary who died an atheist. Zizek is right to a degree, but he is not "heretical" enough. To be truly heretical, we must live in the realm forged by a crucified and resurrected revolutionary. To live in light of crucifixion is foolishness; even heresy. To live in the light of resurrection means that that heresy is our only hope.
To find out more about what Zizek means by his quote above, you could spend an hour and a half watching this lecture. This is the kind of thing normal people do in their spare time, right?