First of all, why would God make people that He dearly loves, and then choose who will go to heaven and those who will go to hell? Why would Jesus die on the cross for people who he has already chosen to live? Why do we need to accept God into our hearts if he has already made up his mind on who should go to heaven? Why should those "chosen" live God's will if their eternity with Christ has already been decided?
What about the people predestined to burn in hell? Is there any hope for them? Will they ever be able to make it to heaven, if they changed their hearts? Why would a God who claims to love everyone, condemn them to eternal suffering? How could He let that happen?
Here is the beauty of free will. God knows who will go to heaven and hell. However, I have no belief that He chooses that for them. I have faith that God allows us to chose the way we want to live our lives. Therefore, it is our choice if we want to serve God or not. What would God care about us letting Him into our hearts if He has already deemed it so? Why did God give minds that think and react and love on their own if we didn't choose to love Him. There is no joy in making someone love you. Why would God want that?
I know that I will be asked to cite a verse so here it is:
For God so loved the world that he gave his one and only Son, that whoever believes in Him shall not perish but have eternal life.John 3:16 (emphasis added)
God has given us free will for a reason. This is another great reason for us to minister to people, because without free will in their choice, what is the point of showing people Christ's love and grace?