1 John 4:14
 And we have seen and testify that the Father has sent his Son to be the Savior of the world. (ESV)
The Apostle John writes that he testifies about what he has seen. Can you imagine what John had actually seen. There were 12 disciples. Of the twelve disciples Jesus spent the most time with three: Peter, James, and John. But of the three, John was referred to as the disciple that Jesus loved. That does not mean that Jesus did not love the others, but John was very close to Jesus.
John was there when Jesus raised Lazarus from the dead. He saw Jesus shed tears of compassion when the Savior saw all of the people mourning the loss of Lazarus. John was there when Jesus fed five thousand people by multiplying the five loaves and two fishes of a small boy. The Apostle would have remembered the death and resurrection of the Savior. There were so many things that John witnessed. Listen to his words in his Gospel:
 Now there are also many other things that Jesus did. Were every one of them to be written, I suppose that the world itself could not contain the books that would be written. (ESV)
John wants us all to know that God the Father sent His Son to be our Savior. It isn't just a philosophical point that John is making. It is not just his opinion. It is not even a theological point he makes from his knowledge of Scripture. He has seen and testified. He saw with his own eyes. John's testimony is an encouragement to all of us that Jesus came to be our Savior!
Spend some time scanning through the Gospel accounts (Matthew, Mark, Luke, and John). Consider how amazing it would have been to be an eyewitness of Jesus on this Earth. Be encouraged as you get to know your Savior.