Philippians 1:5-6

Different opinions on whether one can lose their salvation in Christ. Arminian Position: a Christian can eventually lose their salvation by continually denying/resisting God. Another view is "once saved, always saved." 

Doctrine of Eternal Security: if at some point in your life you truly repent of your sins, accept Jesus as your saviour, and the Holy Spirit comes into your life then He who began a good work in you will complete it.

Objections to this

  • this Doctrine may lead to people being slothful (if you guarantee salvation people may act selfishly and abuse grace by not changing their lives). Everything can be abused/misapplied, that does not make it false. In context, when Paul was writing to the Philippians, they were already persevering in the gospel, so the message was one of encouragement rather than a temptation to slack off. This promise of God always being there can give psychological security (blessed assurance).
  • what about those that appear to walk away from the faith? For cases like Judas, Jesus says that Judas was never saved to begin with and He knew Judas was going to betray Him. The promise of being perfected is that we will be complete when Jesus comes again, not upon our death. 1 John 1:19 God is the author and finisher of our faith - salvation is an ongoing process that He is in charge of and He is not limited in the ways we are.