That thou mightest know the certainty of those things, wherein thou hast been instructed.
John 20:31
But these are written, that ye might believe that Jesus is the Christ, the Son of God; and that believing ye might have life through his name.
2 Peter 1:15
Moreover I will endeavour that ye may be able after my decease to have these things always in remembrance.
2 Peter 1:16
For we have not followed cunningly devised fables, when we made known unto you the power and coming of our Lord Jesus Christ, but were eyewitnesses of his majesty.