It would be fair to say many people had problems in what Jesus taught. In particular though, the religious authorities did to the point of eventually planning and enacting the pathway for His death.
The teachings that came from religion and not the Bible.
From the Bible
The Bible is where the written teachings of Jesus are kept.
You have it a little backwards my friend. The Bible is based on Jesus' teachings. Specifically the first four books of the new testament. Jesus refers to the old testament sometimes in his teachings but they were not based on them.
The Holy Bible.
You put one Jesus by following His principles and teachings. His principle and teachings are found in the bible.
Because Jesus was the Christ, Christianity is the faith that purportedly follows the teachings of Jesus. However, most Christian religions following the teachings of the epistle writer Paul instead. For example, Jesus says in the Bible "I am not here to start a new religion but to bring a new covenant." The fact that there are religions that follow the teachings of Jesus is in direct contradiction to his own words.
his crucifixion and resurrection, his teachings and miracles
The written account of Jesus's life and teachings is the New Testament of the Christian Bible.
Most were in the new testament or in Jesus' teachings or some might be in the old testament when it talks about the prophets and their teachings.
The Bible is fundamental in understanding who Jesus is, as his teachings and life are written about by those who lived alongside him in at least 4 "books" and all the background for us to understand why he did what he did and where he did it, is in the rest of the Bible.
It is important as it shows what wil happen in the future, and the teachings of Jesus and warning are there.