Well, it also tells you that he is god. One such "telling" being based on basic logic (law of transitivity:. If A is B, and B is C, then A is C.)
John 1:1, "In the beginning was the Word, and the Word was with God, and the Word was God."
So, what is this "Word"?
John 1:14, "And the Word became flesh, and dwelt among us, and we beheld His glory, glory as of the only begotten from the Father, full of grace and truth."
Which would be the being called Jesus.
So, Jesus
is god.
From the above (John 1:1, 14) it's clear that Jesus is god.
........
And, if Matthew 3;17 is true
"and behold, a voice out of the heavens said, "This is My beloved Son, in whom I am well-pleased." (the Son being Jesus)
then it's quite clear that Jesus is the son of himself.