John 1:1-5,14,17-18 (New International Reader's Version)
1 In the beginning, the Word was already there. The Word was with God, and the Word was God. 2 He was with God in the beginning.
3 All things were made through him. Nothing that has been made was made without him. 4 Life was in him, and that life was the light for all people. 5 The light shines in the darkness. But the darkness has not understood it.
14 The Word became a human being. He made his home with us. We have seen his glory. It is the glory of the one and only Son. He came from the Father. And he was full of grace and truth.
17 Moses gave us the law. Jesus Christ has given us grace and truth.18 No one has ever seen God. But God, the one and only Son, is at the Father's side. He has shown us what God is like.
Philippians 2:6-8 (New International Reader's Version)
6 In his very nature he was God. But he did not think that being equal with God was something he should hold on to.
7 Instead, he made himself nothing. He took on the very nature of a servant. He was made in human form.
8 He appeared as a man. He came down to the lowest level. He obeyed God completely, even though it led to his death. In fact, he died on a cross.
The single most divisive issue that has always faced Christianity is the existence and nature of Jesus. This sets Christianity apart from all of the other faiths, and it has even led to divisions among those who call themselves "Christian" as well. This dispute is what ultimately caused the execution of Jesus, because although Jesus was fully a man, he represented himself to be equal to God:
John 5:17-19 (New International Version)
17Jesus said to them, "My Father is always at his work to this very day, and I, too, am working." 18For this reason the Jews tried all the harder to kill him; not only was he breaking the Sabbath, but he was even calling God his own Father, making himself equal with God. 19Jesus gave them this answer: "I tell you the truth, the Son can do nothing by himself; he can do only what he sees his Father doing, because whatever the Father does the Son also does.
There is no question in my mind or the mind of scholars over the past two thousand years that Jesus existed. Although there is some dispute that the entire passage is genuine to the author, the Jewish historian Josephus wrote in the late 1st Century about Jesus in his Testimonium Flavianum, as it is popularly called:
Antiquities 18.3.3 Now there was about this time Jesus, a wise man, if it be lawful to call him a man, for he was a doer of wonderful works, a teacher of such men as receive the truth with pleasure. He drew over to him both many of the Jews, and many of the Gentiles. He was the Christ, and when Pilate, at the suggestion of the principal men among us, had condemned him to the cross, those that loved him at the first did not forsake him; for he appeared to them alive again the third day; as the divine prophets had foretold these and ten thousand other wonderful things concerning him. And the tribe of Christians so named from him are not extinct at this day.
I have linked to the comments to the passage and the criticisms for and against authenticity, and I would suggest that you read the foundations for this secular reference to the existence of Jesus.
In addition to this and other secular references, the holy book of Islam, the Qur'an, supports the existence of Jesus. Jesus is mentioned 25 times in the Qur'an and although Muslims believe Jesus was a prophet from God before Muhammad, the very fact that Islam chooses to define Jesus' nature validates his existence. The Qur'an was written in the 7th Century, and if you take time to read the passages, you will find many parallels to Biblical writings about Jesus, with a slight twist to conform to their theology. Wikipedia does a good job of covering this topic, and you can find great links to English versions of the Qur'anic passages about Jesus to study for yourself.
Where am I going with this? Well, to study and comment on the nature of Jesus, you need to first agree that he exists and walked this earth, and in providing extra-Biblical support I seek to answer any arguments that someone might have against this fact.
(A careful study of these and other secular and Christian sources can be found referenced at KnowWhatYouBelieve.com.)