One of the biggest proof that Jesus was truly who/what He claimed He was is the martyrdom of his followers.
Every one of his disciples except for Apostle John was killed. One was crucified, one was skinned alive and crucified, one was stabbed and then beheaded, one had his head bashed in with a club, one was speared to the ground, the list goes on, but you get the gist, there was no nice, happy ending surrounded by riches, wealth and honour for a follower of Jesus.
What would have convinced them to go through this?
Well, you would argue that people from other religions also do things that get them killed in the name of religion.
There is a very major difference.
People who kill/get killed in the name of religion these days have not directly seen their god. They have received all their information second hand i.e. from their religious teachers, places of worship, parents, their holy books etc. It is easy to brainwash people if you teach them a certain way from their childhood, you can drum into them whatever you want them to believe. However it is not possible brainwash people who have seen things first hand.
Let me explain further. Suppose I claim to be god and go around teaching it. I get a group of followers and they start living with me and being with me 24 x 7. One day when going around with my followers I come across a group of thugs who stab and kill me for my wallet. I then get buried and that’s it, end of story.
What do you suppose my followers would do? The person they followed, who claimed to be god, was killed by some thugs and is now gone. If someone were to come up to one of them and threaten to drop them alive into boiling oil unless they disown me, what do you think they would do?
Now contrast that with Jesus’ disciples. They saw their master being captured, tortured, crucified and buried. Every one of them ran away and hid themselves. What caused the change in them to then come out and start proclaiming that Jesus was God at the threat of persecution, hunger, torture and death? What did they have to gain? Please take time to think about this.
Like I mentioned above, you can brainwash people but only if they haven’t seen things first hand. It is not possible to convince someone to get tortured/killed/separated from their family for someone they knew intimately unless they were truly convinced that the person was who they claimed to be.
We have seen his glory, the glory of the one and only Son, who came from the Father, full of grace and truth. John 1:14.