God's plan to save mankind was established before the foundation of the world. When the Israelites were at their point of distress due to Romans ruling their land and also due to their own individual problems such as sickness and bondage to evil, they were looking for a Saviour who could save them. It was during this time that Jesus was born and he revolutionized the Jewish community in their beliefs and practices. Because of this, Jesus was hated by the religious leaders of the day and they plotted to kill him.
When Jesus was crucified on the cross, it was not a defeat to the plan and purposes of God. It was actually a victory. As it was required for the people to offer the blood of an animal for the cleansing of their sins, Jesus replaced that animal by offering himself as the sacrifice for sins. The shed blood of Jesus paved the way for mankind to be forgiven of their sins. When Jesus rose from the dead, he declared his followers to be righteous in the sight of God. People even today are saved when they place their faith in Jesus Christ and believe in their heart that God raised Jesus from the dead.