On an issue like this the Bible is not silent. Assurance of salvation is important. Therefore God, through His word, teaches us how we can determine if we are truly born again. In fact the book of first John's main purpose is to show how we can have assurance. Without this assurance we are like a soldier running into battle without his helmet, exposed to many attacks.Without this assurance we are like soldiers in a battle always doubting which side we are fighting for and who our enemy is. Assurance of salvation gives us courage. We know without a doubt which side we are fighting on. We know that victory is ours through Christ. We know that Jesus Christ and all His infinite resources are at our disposal. As you see, it is very important that we gain a great assurance that Jesus is our Savior.
Assurance of salvation is not gained by man's thoughts and ideas. Our baptism will not give us real assurance of salvation. If you were baptized as a baby or later in life it doesn't contribute one bit to your salvation and thus, neither to your assurance of salvation. Just because you said a prayer or came at an altar call or made a profession of faith, doesn't mean you will have a real assurance of salvation. Assurance doesn't come by working in the church, missionary enterprises or sacrificial giving. All these may give a false assurance, which is damning and dangerous to the soul. But only the word of God truly give a person the way to a true and lasting assurance of salvation.
Maybe you are skeptical that God even calls us to consider whether we are true Christians. Some might say this kind of examination is unhealthy. Is there a clear command in scripture to test whether we are indeed saved from the wrath to come? Yes there is. In 2 Corinthians 13:5 we read this, "Test yourselves to see if you are in the faith; examine yourselves! Or do you not recognize this about yourselves, that Jesus Christ is in you- unless indeed you fail the test?" After listing a number of virtues, Peter says this in 2 Peter 1:10, "Therefore, brethren, be all the more diligent to make certain about His calling and choosing you; for as long as you practice these things, you will never stumble;" As I said John's first letter was meant to lead Christians toward assurance of salvation. Consider John's purpose statement for this letter. "These things I have written to you who believe in the name of the Son of God, so that you may know that you have eternal life." 1 John 5:13
These verses make it clear that God wants us to test ourselves so we are not fooled into thinking we are Christians when we are not and that God wants His people to be confident of their salvation in Christ. In further posts I want to look at the questions on the 'Am I a Christian?' test.