In the book of 2 Corinthians, Paul writes this:
2 Corinthians 3:5 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?
Paul tells the Corinthian believers (and us) to examine ourselves—to test ourselves to see if we are in the faith—to see if our faith is genuine and real. That may seem to go against the idea of assurance to you. But, a true believer will want to examine himself; he will want to see evidences of the work of God in his life. And when he does, it will give him sweet assurance.
Paul asks, “do you recognize that Jesus Christ is in you?” When we test ourselves, we will either recognize that Christ is in us, or we will fail the test.
The book of First John gives us several tests to know that we are in the faith. Gary gave a message recently on six of these tests by which we can examine our faith. Click on this link to download the text of the message.