'At that moment' refers to the cry of Jesus in which He surrendered His Spirit to Father God, and died. The atoning sacrifice was complete, sin had been punished and the weight of God's justice had fallen on Jesus. At that moment two dramatic events shook the city. Something most powerful had happened.
 
The temple curtain shut off the place in the temple where God chose to be present, from even the most ardent worshipper. Only one priest could go in, and then only once a year. The curtain was modelled on that in the tabernacle (Exodus 26:31-33). Josephus, the Jewish historian described it as being over fifty feet tall and four inches thick; it was so strong that even two horses attached to its sides could not tear it. But when sin's power was defeated, the curtain was torn from top to bottom. Suddenly, there was free access to Father God. The death of Jesus had opened the way for people to know God.
 
An earthquake split open the rock tombs. The power of death had been defeated. It was undeniable as many people, who had lived and died trusting the Word of God and looking forward to the Messiah, were given new bodies to walk around in the city and meet many people. There was no doubt that the death of Jesus had broken the curse of death.
 
The death of Jesus was no accident: God planned it. It was no tragedy: Jesus broke the power of death for everyone who believes. It was not just a kind example of self-giving; it was a crushing defeat for Satan and releasing of his captives. Once the punishment for sin was paid, nothing could hold God's people back. There was immediate access to His presence with new life to serve Him. If you are trusting in Jesus, you are not just a part of a religious club – you have been set free from the grip of Satan to serve the Lord. That is why the gospel is earth-shaking news for the people who live in darkness and fear. So, live your new life with joy and tell others how it is possible for them too.