1 John 5:13

¹¹ And this is that testimony: God has given us eternal life, and this life is in His Son.

¹² Whoever has the Son has life; whoever does not have the Son of God does not have life.

I have written these things to you who believe in the name of the Son of God, so that you may know that you have eternal life.

¹⁴ And this is the confidence that we have before Him: If we ask anything according to His will, He hears us.

¹⁵ And if we know that He hears us in whatever we ask, we know that we already possess what we have asked of Him.

Do read the surrounding verses too, because the context often says more than a single verse.

Compare

BSB: I have written these things to you who believe in the name of the Son of God, so that you may know that you have eternal life.
KJV: These things have I written unto you that believe on the name of the Son of God; that ye may know that ye have eternal life, and that ye may believe on the name of the Son of God.
WEB: 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, and that you may continue to believe in the name of the Son of God.
ASV: These things have I written unto you, that ye may know that ye have eternal life, [even] unto you that believe on the name of the Son of God.
DARBY: These things have I written to you that ye may know that ye have eternal life who believe on the name of the Son of God.
BLB: I wrote these things to you⁺, the ones believing in the name of the Son of God, so that you⁺ may know that you⁺ have eternal life.

ÅB: Dette har jeg skrevet til dere for at dere skal vite at dere har evig liv, dere som tror på Guds Sønns navn.
OTB: Jeg har skrevet disse tingene til dere som tror på Guds Sønns navn, for at dere skal vite at dere har evig liv.
B1930: Dette har jeg skrevet til eder forat I skal vite at I har evig liv, I som tror på Guds Sønns navn.

John 20:31
But these are written so that you may believe that Jesus is the Christ, the Son of God, and that by believing you may have life in His name.
Read in context
John 1:12
But to all who did receive Him, to those who believed in His name, He gave the right to become children of God—
Read in context
1 John 3:23
And this is His commandment: that we should believe in the name of His Son, Jesus Christ, and we should love one another just as He commanded us.
Read in context
2 Peter 1:10–11
Therefore, brothers, strive to make your calling and election sure. For if you practice these things you will never stumble,
Read in context
John 3:18
Whoever believes in Him is not condemned, but whoever does not believe has already been condemned, because he has not believed in the name of God’s one and only Son.
Read in context
1 John 2:21
I have not written to you because you lack knowledge of the truth, but because you have it, and because no lie comes from the truth.
Read in context
1 Timothy 1:15–16
This is a trustworthy saying, worthy of full acceptance: Christ Jesus came into the world to save sinners, of whom I am the worst.
Read in context
Galatians 4:6
And because you are sons, God sent the Spirit of His Son into our hearts, crying out, “Abba, Father!”
Read in context