Answer — Absolutely not. Is backsliding a sin? Of course it is. How many sins did Jesus Christ pay for on the cross? His blood covered every single sin. Note Acts 10:43 —…Through his name whosoever believeth in him shall receive remission of sins. Also, 1 John 2:12 says, I write unto you little children, because your sins are forgiven you for his name’s sake.
Ephesians 2:8-9 also tells us, For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast. If we had to stay right with the Lord in order to stay saved, then that would be salvation by works. Salvation would no longer be a gift.
This doesn’t mean you should live in sin after salvation. Now that you know Christ as your Savior, you have the Holy Spirit living inside you. You now have the power not to sin. Works are never a requirement to receive or maintain salvation.