And I will show wonders in the heavens and on the earth, blood and fire and columns of smoke. The sun shall be turned to darkness, and the moon to blood, before the great and awesome day of the LORD comes. And it shall come to pass that everyone who calls on the name of the LORD shall be saved. For in Mount Zion and in Jerusalem there shall be those who escape, as the LORD has said, and among the survivors shall be those whom the LORD calls. (Joel 2:30-32)
Both of these passages refer to our salvation through the death and resurrection of Jesus Christ, and both of them make it clear that this was always God's plan. John calls back to the creation of the universe through Jesus and highlights how amazing was Jesus' incarnation as a man. John then describes exactly what kind of difference Jesus has made: that all those who believe become born of God rather than of man, and are no longer in the sins of their flesh but alive in the spirit of Christ.
Joel makes clear the long-term plan behind the resurrection through the simple textual device of predating Jesus' birth by at least six centuries (though the plan is as old as the universe). All through Israel's earlier tribulations God was promising them both short-term deliverance and an eventual total salvation from sin - available to all those who believe, who 'call on the name of the LORD' and believe.
But not everyone calls and believes. From just these two slices of scripture, and from the world around us, we can see that not even most people call and believe. Salvation is being stretched out to us but so few reach for it - and only those who do will survive the punishment to come. We must always be joyful in the knowledge that Jesus' victory over death was total and entirely according to plan, and we must not forget that it is a sacrifice that demands a response. We must call and believe.
Jesus Christ, you died for my sins and rose again. I am yours.