Dusty idea is the idea that I might be lost. What is lost? It means that you have died in your sins, and you will go to Gehenna or hell as described by Jesus in Matthew the 25th chapter. You will be in outer darkness for all eternity.
Most people you see will tell you that when they die they want to go to heaven. Most people aren't making any preparations to go there though. It's like the person that wanted to be a doctor when they grew up, but didn't want to study anything in school. They want, and they hope, but without any preparation how many patients do you think they'll get as a doctor? I know some people have fake degrees and get by with things for a while or maybe never get caught playing doctor. I promise you your fake Christian degree isn't going to fool God. You're not going to duck and dodge or slip and slide into heaven on some kind of accidental thing that God somehow forgot about you. If you go to heaven it will be because you have heard the Gospel of Jesus Christ1. It will be because you believe it2. Then you repented3 of sinful practices. You confessed4 Christ as the Son of God. Then you contacted the blood of Jesus through baptism5 (not infant baptism but an accountable age), which blood washed6 your sins away. Then you continued following Jesus, seeking to save that which is lost7. Converting people like you once were. Then The Lord wrote your name in the Lamb's Book of Life8. Then you worshiped right, worked right and walked right so it wouldn't be blotted out9.
One of the ideas people seem to have is that God is going to just go around saving random good people or good as the world defines good. There aren't any good people Mark 10:18. Ephesians 5:23 says that Jesus is the savior of the body, you have to get into the body to be saved. He will not save you outside of the body.
What is the body? It's the Church, Colossians 1:24 Paul says Now I rejoice in my sufferings for your sake, and in my flesh I am filling up what is lacking in Christ’s afflictions for the sake of his body, that is, the church,
Are you in the body? The title of this dusty idea was what must I do to be lost, well here it is: don't do anything listed above in red. Whatever you do don't do that, because it's the only thing that can take you to heaven.
1 Acts 15:7
2 Mark 16:16
3 Acts 2:38
4 Luke 12:8
5 Mark 16:16, Acts 2:38, 1 Peter 3:21, Colossians 2:12
6 Eph. 1:7, 1 John 1:7, Revelation 1:5, Acts 22:16
7 Mark 16:15
8 Philippians 4:3, Revelation 21:27
9 Revelation 3:5