In the book of 1 John, he uses the word "write" or "written", over and over starting in the first chapter, verse 4.  "And these things we write to you that your joy may be full."

Then in chapter 2:1, he says, "My little children, theses things I write to you that you sin not."

John is intent upon conveying that he is putting the truth into written form.  He uses the word "write" 13 times in this short letter.  (One of my friends says it is 14 times, but I can't find that many.)

He sums it all up in the last few verses of the letter--which are my favorite part--this way:  1 John 5: 11-12 "And this is the record, (written) that God has given to us eternal life, and this life is in his Son.  He that has the Son has life; and he that doesn't have the Son of God doesn't have life."  None of the people who knew Jesus was closer to Him than John and he wants you to know Jesus in the same way he does.  

Simple salvation is having Jesus in your life.

The next verse (13) is for you--if you have ever been plagued with doubt.  He is writing it to believers to reassure them.  "These things I have written to you that believe on the name of the Son of God; that you may know that you have eternal life and that you may believe on the name of the Son of God."   

You that believe.....that you may know.....that you may believe.....

The growth of faith occurs as we believe.  God reveals himself to us and our faith grows stronger.  There comes a point that you just know the truth is true.  You have to start somewhere.  The "record" is a good place to start.