That You May Know You Have Eternal Life

These things I have written to you who believe in the name of the Son of God, that you may know that you have eternal life. (1 John 5:13)

John has been writing about eternal life from the beginning of his epistle. His testimony has always been of the Lord Jesus Christ, who is all about eternal life.

From John’s Gospel

For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life. (John 3:16)

He who believes in the Son has everlasting life; and he who does not believe the Son shall not see life. (John 3:36)

“Most assuredly, I say to you, he who believes in Me has everlasting life.” (John 6:47).

“I have come that they may have life, and that they may have it more abundantly.” (John 10:10)

“And I give them eternal life, and they shall never perish; neither shall anyone snatch them out of My hand.” (John 10:28)

“I am the resurrection and the life. He who believes in Me, though he may die, he shall live. And whoever lives and believes in Me shall never die. Do you believe this?” (John 11:25-26)

“I am the way, the truth, and the life. No one comes to the Father except through me.” (John 14:6).

“Father, the hour has come. Glorify Your Son, that You Son also may glorify You, as You have given Him authority all flesh, that He should give eternal life to as many as You have given Him. And this is eternal life, that they may know You, the only true God, and Jesus Christ whom You have sent.” (John 17:1-3)

From John’s epistle:

That which was from the beginning, which we have heard, which we have seen with our eyes, which we have looked upon, and our hands have handled, concerning the Word of Life—the life was manifested, ad we have seen, and bear witness, and declare to you that eternal life which was with the Father and was manifested to us. (1 John 1:1-2)

And this is the promise that He has promised us — eternal life. (1 John 2:25)

We know that we have passed from death to life because we love the brethren. He who des not love his brother abides in death. Whoever hates his brother is a murderer, and you know that no murderer has eternal life abiding in him. (1 John 3:14-15).

And this is the testimony: that God has given us eternal life, and this life is in His Son. (1 John 5:11)

These things I have written to you who believe in the name of the Son of God, that you may know that you have eternal life. (1 John 5:13)

We know that the Son of God has come and has given us an understanding so that we may know Him who is true; and we are in Him who is true, in His Son Jesus Christ. This is the true God and eternal life. (1 John 5:20)

How to know
It is possible to know that we have eternal life, and that is why John writes. The reasons for how we can know are all throughout the epistle.

• We can know by the fellowship we have with the Father and with the Son (1:3).
• We can know by walking in the light, for God is light, and the blood of Jesus cleanses us from all sin (1:5-7).
• We can know by God’s faithfulness to forgive us and cleanse us from all unrighteousness (1:9).
• We can know by the anointing of the Holy Spirit in us to teach us all things (2:20, 27).
• We can know by abiding—Him in us and us in Him (2:27).
• We can know by the love of God at work in us and through us (3:16-19; 4:7-11, 20-21).
• We can know because our heart does not condemn us (2:20-21).
• We can know because we do what is pleasing in His sight (2:22), for without faith it is impossible to please Him (Hebrews 11:6).
• We can know because we believe on the name of His Son Jesus Christ and love one another (3:23-24).
• We can know because we confess that Jesus Christ has come in the flesh (4:1-3).
• We can know because He who is in us is greater than he who is in the world (4:4-6).
• We can know because He has given us of His Spirit (4:13).
• We can know because we confess that Jesus is the Son of God (4:15).
• We can know because we have known and believed the love that God has for us, for God is love and he who abides in love abides in God, and God in him (4:16).
• We can know because there is no fear in love, but perfect love casts out fear (4:17).
• We can know because He first loved us, and we love Him in return (4:19).
• We can know because we believe that Jesus is the Christ, the Messiah, the Anointed One (5:1).
• We can know because we love God and keep His commandments (5:2-3).
• We can know because we overcome the world, and the victory that overcomes the world is our faith (5:4). We overcome because we believe that Jesus is the Son of God (5:6).
• We can know because of the water—1) the baptism of Jesus, by which He identified with us in or sin. 2) the sign of water baptism by which we identify with His life, His righteousness and His resurrection (5:7-8).
• We can know because of the blood of Jesus, shed for us, which cries out on our behalf (5:7-8, see also Hebrews 12:24).
• We can know because of the Holy Spirit bearing witness (5:7-8).
• We can know because He who has the Son has life (5:12).
• We can know because if we ask anything according to His will, He hears us. And it we know that He hears us, whatever we ask, we know that we have the petitions we have asked of Him (5:14-15).
• We can know because the Son of God has come and has given us an understanding, that we may know Him who is true, in His Son Jesus Christ. This is the true God and eternal life. (5:20).
  

Now, understand that this is not how we have eternal life. We have, or receive, eternal life purely by faith in the Lord Jesus Christ. Rather, this is how we know that we have eternal life. These things give us the assurance that eternal life is indeed at work in us.

If you believe in the name of the Son of God, then you can know you have eternal life.