The idea of Jesus being just a good man or even just a prophet does not consider what He said about Himself.
18 The wicked earns deceptive wages, but the one who sows righteousness gets a sure reward.
Jesus didn’t pull any punches about who He was or why He was there. Let’s look:
40 But now you’re trying to kill me – me, a man who has told you the truth which I heard from God! That’s not what Abraham did.
42 ‘If God really was your father,’ replied Jesus, ‘you would love me, because I came from God, and here I am. I didn’t come on my own initiative, you see, but he sent me. John 8:40, 42
54 ‘If I do give myself glory,’ replied Jesus, ‘my glory is nothing. My father is the one who brings me glory – the one you say is “our God”; 55 and you don’t know him! I know him, though. If I were to say I didn’t know him, I would be a liar like you. But I do know him, and I keep his word. John 8:54-55
58 ‘I’m telling you the solemn truth,’ replied Jesus. ‘Before Abraham existed, I Am.’ John 8:58
This last one really got them. Jesus was assuming the title that God used when conversing with Moses. And, sure enough, they picked up stones to throw at Him (v.59), but it still wasn’t His time. He was headed to Passover to become the ultimate Passover lamb. Jesus loved us so much that He allowed evil men (representative of all mankind) to kill Him rather than give them what they deserve (that’s called grace–receiving what we need rather than what we deserve). It is through His grace that we receive His gift of life.