Hebrews 2 seems like a good first chapter to read after you become a Christian. Whether you begin with verse 5 or 9 you get a great description of the basics. Jesus was and is God. He became human so that He could experience temptation just as we do, yet not succumb to it. Once He had remained faithful and pure after being tempted, He surrendered His life as a substitute for our own. In this way, every person who says to God (aloud, or in quiet prayer) “I have heard the account, and I believe it happened just as you have told me. I believe that Jesus is real, He did die for my sins, and I would like to ask for forgiveness right now. Please forgive me, accept me as your child, in your kingdom, amen”
Every person who prays that way receives forgiveness. They immediately receive adoption. Now they are sons and daughters of a great King who is the Creator. Of course we don’t have to use those exact words. I sometimes think that far fewer words than these will net the same result. Perhaps there are others for whom it will take more. The exact verbiage isn’t the issue, it’s the desire of the heart that is truly important.
One stray thought: how could we be guilty of “drifting away” if we hadn’t arrived in the first place? The language here seems to imply that once we have “docked our boat” on the shore with Jesus we can still drift if we don’t remain obedient. That suggests that remaining “in Christ” takes some effort and attention on our part. That is no doubt why the Holy Spirit remains with us, and in us. Without Him, we wouldn’t be able to remain, and without remaining we wouldn’t be able to enter heaven. We need to stay close. Think of it like “dropping an anchor” next to Jesus. If you pull the anchor up, then the boat will eventually drift off, and you will no longer be in the harbor. I fear that those who preach that you accept Christ and then stay “secure” without any change in behavior are incorrect.