An eye for an eye meant an actual eye for an eye. The Pharisees felt the oral tradition could be interpreted as an eye could be replaced for the value of the eye. Although both the Sadducees and Pharisees fought against each other, both group groups disapproved of Jesus. Both believed in one God. Jesus was preaching that He was the Messiah.
Instead of the law that both Sadducees and Pharisees believed in, Jesus was preaching forgiveness and love. While the Sadducees did not believe in an afterlife, the Pharisees thought the way to heaven was by following the law. When Jesus tore down the money changer tables in the Temple, both groups decried him as a sacrilege. Jesus came preaching new concepts that the Jews did not want to listen to at the time.
I believe the pivotal event in the emergence of Christianity between Jesus’ death and the end of the Roman Empire was the conversion of Roman Emperor Constantine I. I think if any other Roman Emperor such as Caligula, Nero, or any other save for Constantine had promoted Christianity than Christianity would have remained a cult and not grown. However since Constantine I had many military victories and his greatness helped promote Christianity.
In Catholicism anyone baptized is saved. Children are baptized as soon as possible to save their immortal soul. This practice uses baptism as a way to be saved. On the other hand, Calvinists believe only someone who has accepted Jesus in their heart should be baptized. A preacher must talk and be convinced of the individual’s sincerity. This type of baptism is used to show they have been saved. For a Calvinist to submit to a baptism and not be saved only infuriates God. It would be better to be saved and not baptized than be unsaved and baptized.
Two theological issues that caused the Reformation was King Henry VIII declaring himself not under the authority of the Pope. Henry became head of the new English Church. The second theological issue was the Bible.