God does not change. His plans were decided long ago.
But 'decided' does not mean revealed.
Imagine a long scroll. On it are words written with God's handwriting. The text includes the life and name of every person who ever lived. It includes every purpose of God, every move of the Spirit, the life of Jesus and even activities of the spiritual world. It is the account of history, perfectly written before any of it took place. Then in was rolled up, starting with the end and finishing with the beginning.
In the beginning, when God created the world, He began to open the scroll. The steady opening became the mandate for time. The unfolding can never be sped up or slowed down. First creation, then fall, then the deaths of Adam and Eve's spirits. The scroll unrolls further revealing the curse and the beginning of the deaths of Adam and Eve's physical bodies. Then God opened the part of the scroll that we read about in Genesis 3. It is a glimpse of God's plan to redeem humanity; to bring us back to the fullness of life!
But God did not reveal His entire plan all at once. He revealed it in time, with the steady unrolling of the scroll of history. Sometimes He gave more information about the plan to certain individuals who trusted Him; men like Noah, Abraham, Isaac, Jacob and David. Anyone who has trusted in God has been granted the privilege of understanding parts of God's plan. We also get to be part of His plan to bring life back to humanity and bring the kingdom of Heaven to earth. Those who have chosen not to believe in God or trust Him are not given the gift of understanding. They choose not to be part of God's plan.
Trusting in God and His plan has always been and always will be what makes all the difference between understanding and life, and not understanding and death.
As the scroll of time and the unfolding of God's plan has been steadily unrolling and new parts of it have been revealed, those who trust God and those who don't have become evident.
For example, during the first century Jesus was teaching people about the way He would make for their spirit's to be made alive again and for their bodies to be remade in the future. (John 3) This news was being widely spread. The Prophets from the Old Testament has alluded to this future promise and many people believed it and accepted as part of God's plan. Many also rejected it. Jesus and the disciples also revealed that this way was available to the whole world, anyone who trusted God and His son Jesus, not just the Israelites, even though Jesus was an Israelite. This part of God's plan was difficult for some people to understand and accept. But, for those who trusted God, they were given understanding.
This happened to one man named Barnabas. He was living in Jerusalem and was teaching the Jews God's way of life through Jesus. When he and other believers heard that non-Jews in Antioch were also believing and enjoying new life through Jesus, they were surprised. They did not understand that this was part of God's plan. Hewent to Antioch to see for himself what was happening. Because he trusted in God, Barnabas gained understanding; this was God's plan all along. The scroll of time, of history, of God's plan to bring His creation back to life was being revealed. He accepted it and rejoiced.
By contrast, many other Jewish leaders and priests did not trust God. They trusted in their traditions, relational ties to important people and knowledge. Understanding was not given to them. They saw the unfolding of God's plan and rejected it. In their rejection and lack of understanding they viewed Jesus and those who believed in Him as a threat. So, they killed Jesus, and proceeded after Jesus' resurrection to kill many of His followers.
Peter taught, "There is salvation in no one else,
for there is no other name under heaven,
given among men by which we must be saved."
Those who trust God get to understand His plan to bring us back to life. Our spirits are made alive now and our bodies will one day be remade. But for those who don't trust God, the unrolling of time and revealing of God's plans seems like a threat, something to be feared. For them it is...they are right.
Believe. Trust God. Choose life so that you can live!