What happens to our salvation when we backslide?
First of all, let’s be clear. The word backslide does not appear in the New Testament. It has been borrowed from Jeremiah 8:5 where it means to turn away from the Lord and refuse to return.
Such a thing is not possible for a New Testament believer, because our salvation was guaranteed to us the moment we believed. (2 Corinthians 1:21-22, Ephesians 1:13-14)
No one can take us out of the Lord’s hands (John 10:27-30) or separate us from the Love of God that is in Christ Jesus our Lord (Romans 8:38-39).
That means we cannot walk away and refuse to walk away and refuse to come back. Therefore we cannot fulfill the definition of backsliding.
What happens with us is that the intensity of our relationship with the Lord can ebb and flow over time.
The Lord has promised never to lose any of us. (John 6:38-39) And He will go after us and bring us back, like a shepherd rescues a sheep that has wandered off.