Verse 13.— These things have I written. The object the apostle had in writing these things to the believers in Christ is to make them fully understand how they may know of a certainty that they have eternal life. In this letter he gives them many infallible tests and examples by which they can, with certainty and accuracy, determine this matter. That believe on the name of the Son of God. Not only that they may continue to believe, but that they may, with absolute safety, put the fullest possible trust in the name of Christ.