Jesus made his entire life very much like a poem using symbolism to create his religion. He, the Son of God, is the greatest example of the perfect human being. There are additionaly two other deities which Jesus talks about. One, God the Father, one could imagine simply being God, the Universe, etc. The second, the Holy Spirit, something somewhat new created by Him. You see before he died on the Cross he told his disciples that the He would send his "Holy Spirit" to those who followed him to save them.
What you're really seeing I generally look at as the mass therapy of humanity. You see Jesus was an emotionally intelligent genious. If there was a test for such, he'd probably surpass the majority of the top 1%. By instilling an example by which to live, himself, he created a way to change; way to be a better self, your perfect self. Additionally, he told people to call on God the Father for help when it was needed to send His Holy Spirit. This creates a form of unconditional strength and resilience to rely on when shit goes south for lack of a better term. And the Holy Spirit, subconciously, gives them "holy" power, faith, hope, etc. even when there isn't any reason for them to have any. Basically by being the perfect example and creating His religion, just like he used parables (metaphors) in His teachings, he metaphorically developed away to keep people emotionally at their best when there is absolutely no reason to. To help those when there is no possibly way to do so. This isn't co-dependency, it's a belief. A belief is internal, and through this belief people are better off because of it. Some people might say it's a trick but in reality it might just be the best damn trick a person can be fooled by. It's a foolproof emotional resiliency so shockingly adapted that when it appearances at it's best it's mood is spread to others and they too can share in this incredibly feeling.
Not only did he do all this, but he also tied it into Judaism. You see the Hebrews used to sacrifice birds, sheep, etc. to redeem them of their sins and take the place of the punishment of death they deserve from God. But being the "Perfect Lamb" Jesus died on the cross (whether he did or not) as the Son of God to take away the sins and horrible past of His followers forever, instead of constantly having to redeem themselves. Jesus realized that people always make mistakes and by saying he died on the cross for their sins like one would sacrifice a lamb, he made it so people don't have to regret their future mistakes, don't have to redeem themselves, don't need to fall back to their old lives. Instead they can continue on to be their perfect selves, forgive themselves as well as others, and continue to show compassion.
The cross is meerly another form of symbolism related to Judaism to create an emotional resilience. It's not anything special in itself besides the fact that it was an incredibly dishonorable and horribly painful way to die which was famous at the time. And through this pain and dishonor, Jesus beared the punishment that one would feel thy deserve for what they've done so that the person desiring to change can simply be the beautiful person they desire to be.
