The OSAS crowd look for scriptures to insinuate that no matter how much you sin or how evil you are, you are still going to heaven and heaven therefore will be filled with evil.
First off, not everyone that believes in Christ will make it past Judgment Day.
Matthew 7:21-23 “Not everyone who says to Me, ‘Lord, Lord,’ will enter the kingdom of heaven, but he who does the will of My Father who is in heaven will enter. “Many will say to Me on that day, ‘Lord, Lord, did we not prophesy in Your name, and in Your name cast out demons, and in Your name perform many miracles?’ “And then I will declare to them, ‘I never knew you; DEPART FROM ME, YOU WHO PRACTICE LAWLESSNESS.’
Practicing lawlessness is descriptive of children of the devil and not children of God. (1 John 3:10) The demons believe in Christ in the same way that these many people in Matthew 7:22-23 believed in Christ with their head and not their heart. Romans 10:10 says it's with the
heart that one
believes unto righteousness. It's one thing to believe in your head "mental assent" that Christ exists and that His death, burial and resurrection "happened" and yet another thing to
trust in the death, burial and resurrection of Christ as the ALL-sufficient means of our salvation. (Romans 1:16; 1 Corinthians 15:1-4)
Matthew 7:21 - Not everyone who says to Me, 'Lord, Lord,' will enter the kingdom of heaven, but he who
does the will of My Father who is in heaven will enter.
John 6:40 - For
my Father’s will is that everyone who looks to the Son and
believes in Him shall have eternal life, and I will raise them up at the last day.
These many people (unbelievers) in Matthew 7:22 had the
wrong foundation. They were
trusting in their works to save them and NOT IN CHRIST ALONE. Jesus
never knew them which means they were
never saved. Their hearts were not right with God, so their "attempted external obedience" (apart from the righteousness of God which is by faith and the blood of Christ) was stained with sin.
John 17:3 - And this is eternal life, that they may
know You, the only true God, and Jesus Christ whom You have sent. The term "know" implies intimate, experiential knowledge, through a relationship with Him, not merely theoretical knowledge. These many people in Matthew 7:22-23 were not true converts.