Jesus was son of God, who came to earth to help the sinner not for the people who already know about Jesus, also Isaiah the prophet told us Messiah will come, who will prepare our way. (Mark 1:2).
Jesus baptized by John the Baptist, and he started his job by hearing the people who suffering by physical illness (sinner) and to preach and taught to his disciples. He came to earth as a miracle worker, since he baptized, he fought forty days with evil spirit, later he started collecting (?) his disciples for teach and show them about God as love through his miracles: Drive out an evil spirit, healing blind men, calmed the storm, fed five thousand and later four thousand, and walked on the water.
Jesus was amazing miracles to hearing the sinner also he told us, I'm the lord even the Sabbath. (Mark 2:28) as a God, for the people who believed only old testament it was hard to believed this, because of this the people had to separated in two ways, like beavers and not believers (about the Jesus as a Son of God), specially a lot of Jewish had jealousy about him, and that was a cause, to kill him later. At the same time, Jesus taught the new kingdom (heaven) and new way to think about Christianity (Love) first time in the Bible Jesus told us about Children and women, he cared them as equal like men. He educated people as a teacher who from God as a son (actually he is a son) and not like prophet. He was poor men who does not have anything so he could understand what is Christian life in that moment, how hard to live with Roman people as a lower class people but he came to clean there sin and to safe them from the sin.
He already predicted about his death to the disciples and later he arrested by roman solders and he betrayed from Jewish, he crucified. .
After the crucified, he resurrected from the death and he told us he promised that he will comeback again to save from Satan.