The Apostle Peter, an eye-witness, testifies in 2 Peter 1:16-19

We did not follow cleverly invented stories when we told you about the power of the coming of our Lord Jesus Christ, but we were eyewitnesses of his majesty.  For he received honor and glory from God the Father when the voice came to him from the Majestic Glory saying, "This is my Son, whom I love,  with him I am well pleased."  We ourselves heard this voice that came from heaven when we were with him on the sacred mountain. (Mark 9:2-8)

And we have the word of the prophets made more certain, and you will do well to pay attention to it, as a light shining in a dark place until the day dawns and the morning star rises in your hearts.

Romans 5:6-10

You see, at just the right time, when we were still powerless, Christ died for the ungodly.  Very rarely will anyone die for a righteous man, though for a good man someone might possibly dare to die.  But  God demonstrates his own love for us in this:  While we were still sinners, Christ died for us. 

Since we now have been justified through His blood, how much more shall be we be saved from God's wrath through Him!   For if, when we were God's enemies we were reconciled to Him through the death of His Son, how much more, having been reconciled, shall we be saved through His life!