That's exactly the point.
So, be careful how you build!
...each one must be careful how he builds.
[...]
If anyone builds on this foundation (Christ - 1 Corinthians 3:11, Ephesians 2:20) using gold, silver, precious stones, wood, hay, or straw, his workmanship will be evident, because the Day will bring it to light. It will be revealed with fire, and the fire will prove the quality of each man’s work. 1 Corinthians 3:10-13
If you add people to the church who are nothing more than wood, hay, or straw (people who will be consumed in the judgment - Isaiah 33:11-12), they won't be saved, but you yourself may be saved, but you will not have them as your joy, and your crown of boasting in the presence of our Lord Jesus at His coming (1 Thessalonians 2:19, Philippians 4:1, Philippians 2:16, 2 John 1:8). You will have labored for
nothing. No reward.
And that's the danger of the Osas type-2 gospel. If you tell 'believers' they can live in their old unchanged, unrepentant lives of unrighteousness of the unbelieving and still be saved, instead of in the new transformed lives of the believing, you are laboring for that which will not last. You are building wood, hay, and straw, instead of gold, silver, and precious stones onto the foundation stone of Christ in the temple of God. Like the land and the branches that will be burned, and the bundles of weeds that are tossed in the furnace, so your work will be destroyed in the fire of the coming judgment and you will have no reward for your labor in the field and building of God.