Q. How can I know for certain that I will go to heaven? I have of course recognized my sin and asked the Lord into my life to take control of all of it.
What you’re asking about is sometimes known as “assurance of salvation.” It’s one of the main themes of the biblical book of First John, so I’ll answer your question from that book. What we find there is that there isn’t one single means by which we get assurance; rather, it comes through a combination of things.
One thing that John writes in this letter is, “We know that we have come to know him if we keep his commands.” He adds, “Whoever claims to live in him must live as Jesus did.” This is sometimes put this way: “Progress in sanctification is necessary for assurance of salvation.” That is, as we find ourselves, as a result of the Holy Spirit’s work in our hearts and lives, living more and more in the way God intends, this assures us that we truly do belong to Him.
Right after this, John says, “Anyone who claims to be in the light but hates a brother or sister is still in the darkness, but anyone who loves their brother and sister lives in the light.” So another sign that God has saved us is that our relationships are transformed. We become more and more able to love others; we live out this love by helping and serving and forgiving them.
A bit later John speaks of those who “went out from us, but did not really belong to us, for if they had belonged to us, they would have remained with us.” In other words, remaining within the community of Jesus’ followers, persevering in the faith, is another sign of genuine belief. “Continue in him,” John says, “so that when he appears we may be confident and unashamed before him at his coming.” God wants us to receive this confidence, this assurance, through the way we see our faith persevere over time and despite difficulties.
Further on John says, “This is how we know that he lives in us: We know it by the Spirit he gave us.” So our awareness of the Holy Spirit’s presence and work in our lives is something that gives us further assurance of salvation.
John does also say, near the end of his letter, “Everyone who believes that Jesus is the Christ is born of God.” So there is indeed an aspect of putting our faith and trust in Jesus as our Savior, as you describe. But the practical themes of living as God commands, loving others, persevering in the faith, and cooperating with the Holy Spirit’s work are woven through the entire letter, like the different themes of a musical composition. So we see that this belief is meant to be manifested in practical ways, and this is what really gives us assurance.
John concludes, “I write these things to you who believe in the name of the Son of God so that you may know that you have eternal life.” So assurance of salvation is clearly something that God wants each believer to have. But it comes from reflecting on our own lives, from recognizing the progress we are making under the influence of God’s Spirit. Confessing our sin and turning our lives over to God is a necessary start. But it’s what God does with our lives from there that gives us the confidence that we truly do belong to Him.
So how about you? Are you finding that, by God’s grace and with His help, you’re more and more able to live as He wishes? Do you have greater love for others, expressed in greater patience, forgiveness, and practical compassion in dealing with them? Are you persevering in your commitment to Jesus, “no turning back, no turning back”? Are you discovering that the Holy Spirit is very much living inside you and bringing about transformation? Then all of these things, building on your initial confession of Jesus as Lord and Savior, should indeed give you confidence that you have “eternal life.”
And that phrase actually means more than going to heaven when you die. It’s not just a quantitative term (life of infinite duration), it’s a qualitative one—it means life that is better and greater because it’s lived in relationship and fellowship with God. And we are meant to enjoy that even in this life.
Good Question 
As always your posts bring me closer to understanding some of God’s mysteries. Thank you