Backsliding is avoidable, but only if we stay humble before God. We all need to "take heed, lest we fall". Pride comes before a fall, so don't over-estimate your immunity to failure. Some say that salvation is predestined, or predestinated, by God; we have no say in the matter. This is often referred to as the "doctrine of election" and it is used to support the concept of "assurance of salvation". It's true that the elect can't be deceived, but it's not because true Christians have no say in the matter. Watch this video to understand this great paradox in Christianity.