Can Christians Walk Away From Their Faith ?
Of course they can - it is called apostasy in scripture - backsliding - departing from the faith.
From Jerome Smith -
"Those who teach unconditional eternal security need to consider whether the direct statements of Scripture affirm apostasy is possible.
One cannot logically be said to depart, fall away, or apostatize from a faith which one never held in the first place.
Paul is addressing these warnings to believers, not unbelievers.
Certainly there would be no point in warning believers against what was impossible."