I
Luke 1:3
it seemed good to me also, having had perfect understanding of things from the very first, to write unto thee in order, most excellent Theophilus,
Luke 1:4
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.
1 John 5:13
These things I have written unto you that believe in the name of the Son of God, that ye may know that ye have eternal life, and that ye may believe in the name of the Son of God.
answer
1 Peter 3:15
But sanctify the Lord God in your hearts, and be ready always to give an answer to every man who asketh you a reason for the hope that is in you, with meekness and fear.