In spite of claims that Jesus is a demon-filled Samaritan, Jesus proclaimed that he knew the Father. But Jesus goes on even further. Jesus proclaimed that Abraham was happy to see Jesus's day (8:56). It's likely that Abraham saw Jesus from heaven (and it also provides evidence that believers in heaven can see events on Earth -- pretty neat stuff).
But that led to another question from the questioners -- how did Jesus see Abraham when he is less than 50 years old? At that time, Jesus made the big proclamation that pretty much marked the straw that broke the camel's back for the questioners of Jesus's time that led to Jesus leaving the temple -- "before Abraham was, I AM" (8:58). The phrase "I AM" has been used as a designation of God from the story of Moses and the burning bush. So there's the confirmation of one of the most well-known concepts in the Bible -- Jesus is God.
For some of you, Jesus as God may be difficult to comprehend or even accept. I get it -- it's a tricky concept even for some theologians. However, here's some information that could help with comprehending or even accepting Jesus as God.
God is one in essence (the what) -- God is the Creator, Ruler, and has a consistent character of holiness, love, and justice. God is three in form/person (the who that is Father, Jesus/Son, and Holy Spirit) -- all of which can exist simultaneously. A close example in real life is polycephalic animals (animals with more than one head), where there are debates on if such animal is considered one or two animal (Wikipedia), though keep in mind that this is an imperfect example. For those who are interested in Trinity for rational thinkers, Homiletic and Pastoral Review has a pretty informative article.
There's also Jesus being God while being human. One idea is that Jesus has the exact same character of God (holy, loving, and just) and with access to God's powerful traits of knowledge and power (based on the same will of both of them to access) but with human limits (AKA why he can die on a cross or only exist in one place at a time).
Knowing that Jesus is God helps explain some of the concepts that Jesus explained, like knowing the Father, having a very strong link to the Father, and having the authority to provide us a way to be free from our past mistakes.