The two previous questions are questions of assurance. Assurance is, “the completeness of conviction and confidence expressed in the life of the believer, worked by the Holy Spirit. It derives from a reliance upon God and His promises alone, and results in boldness and steadfastness in service and in the face of difficulties.”
Many Christians who have walked in the faith for a while, are not totally convinced that they are truly saved. Therefore, they live their lives from spiritual highs, to doubts, to spiritual lows. However, John wanted the first century believers to be absolutely convinced that their faith in Jesus was not a wish. In 1 John 1:1, the writer notes that he saw and touched Jesus. Hence, faith in Jesus gives absolute certainty of eternal life forever.
If you are a believer in Jesus, rest assured that God has given you His Spirit. Eternal life is yours, what a blessed assurance!