How can I know that I am saved for sure?

TL;DR:

You can be sure you’re saved because salvation rests on God’s promises, not your performance. If Jesus saved you by grace through faith, He will keep you, and no one can snatch you from His hand.

Believers' assurance of our salvation comes from the objective truth of God's Word and the promises in it. The Old Testament is filled with God's fulfilled promises (Leviticus 26:12-13). One example is God's promise to Abraham that the whole world would be blessed through His descendants (Genesis 12:2-3), a fulfillment that Jesus noted in His coming (John 8:56).

The main assurance of salvation comes in the New Testament, though. The Bible indicates that those who accept Christ as Savior become God's children (John 1:12) and receive eternal life (John 3:16; Acts 16:31). Scripture teaches that this is a free gift of God, not based on our works (Ephesians 2:8-9). If we didn't save ourselves, we can't unsave ourselves. Jesus made it clear that once we are saved, nothing can separate us from Him (John 10:28-29). The Bible lays out a clear path to salvation: the admittance that we cannot reach God alone and the belief that salvation comes through faith and trust in Jesus alone. Jesus promises that those who have taken those steps are truly saved and cannot be removed from Him, providing assurance of salvation.

from the old testament

God promised Abraham that "all peoples on earth will be blessed through you" (Genesis 12:3), a promise ultimately fulfilled in Christ.
God made many promises, such as to be Israel's God (Leviticus 26:12-13) and protect them (Psalm 121). He fulfilled these promises. The pattern is always that God fulfills His promises.

from the new testament

Anyone who believes in Jesus for salvation has become a child of God: "Yet to all who did receive him, to those who believed in his name, he gave the right to become children of God" (John 1:12). God will not abandon His children.
Believing, or trusting, in Jesus saves us. Paul and Silas told the Philippian jailer, "Believe in the Lord Jesus, and you will be saved—you and your household" (Acts 16:31).
Believers cannot lose their salvation. God's love assures us of that: "For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life" (John 3:16).
Paul affirms that God's love binds us to him, noting that "neither death nor life, neither angels nor demons, neither the present nor the future, nor any powers, neither height nor depth, nor anything else in all creation, will be able to separate us from the love of God that is in Christ Jesus our Lord" (Romans 8:38-39).
When chastising the Pharisees for their unbelief, Jesus contrasted them with those who believe: "I give them [believers] eternal life, and they shall never perish; no one will snatch them out of my hand. My Father, who has given them to me, is greater than all; no one can snatch them out of my Father’s hand. (John 10:28-29). Salvation is not based on our work, but on Christ's (Ephesians 2:8-9). Once we are saved, we are in Jesus' hands and are assured of salvation.

implications for today

"I like you. Do you like me? Check the box yes or no"—As kids, the uncertainty the first crush can be scary. As adults, the uncertainties are bigger: Will my MRI results be okay? Which college should I go to? Should I buy this house? But the most important circumstance in our lives is 100% certain: our salvation.

We can be confident in our salvation because Jesus has said of us, "no one will snatch them out of my hand" (John 10:28). Sometimes the doubts we feel are from ourselves, but they can also come from our enemy, the devil, who would love nothing more than for us to question our identities in Christ. Jesus identified Satan as "the father of lies" (John 8:44). Why should we believe the lie that we can lose our salvation? We shouldn't.

When doubts arise, tune out the enemy, pray to the Father, and open the Bible. Don’t treat your salvation like a checkbox waiting to be marked. It is a promise sealed by Christ, not a feeling to be re-evaluated. Instead of listening to the voice that whispers “What if?”, anchor yourself in the voice that declares “It is finished.”

understand

Christians sometimes doubt whether or not they are truly saved, but our salvation is not based on our feelings.
True salvation comes through belief in Jesus and a life committed to Him.
Our salvation is dependent on God, who holds our salvation.

reflect

When doubts about your salvation arise, how can you remind yourself that it rests on God’s promises, not your performance?
What lies or fears does the enemy try to plant in your mind about your identity in Christ, and how can you counter them with Scripture?
How does knowing that nothing can separate you from Christ's love impact your life and relationship with God?

engage

How can we help each other trust in God’s promises instead of our own feelings when it comes to assurance of salvation?
Why is it important to understand that salvation is a gift of grace and not dependent on works (Ephesians 2:8-9), especially when talking with non-believers?
How might living with confidence in your salvation influence the way you encourage and disciple others in the faith?