Assurance of Salvation... or Lack Thereof

"The plain fact is that Scripture encourages believers to work in righteousness as they reflect the glory of their Lord. And Scripture offers security for those who have this work of grace alive in them. Those who claim belief but do not live righteously are persuaded to fear for their place and are invited to pursue God with all their hearts, minds, and souls that they might rest in the security of God's grace."

(quoted from The Blue Letter Bible)