Now is the time to make justice a reality for all of God's children. ... And when this happens, when we allow freedom to ring, when we let it ring from every village and every hamlet, from every state and every city, we will be able to speed up that day when all of God's children, black men and white men, Jews and Gentiles, Protestants and Catholics, will be able to join hands and sing in the words of the old Negro spiritual, "Free at last! free at last! thank God Almighty, we are free at last!"
Are we all God's children, or only Christians?
The Bible is clear that all people are God’s creation (Colossians 1:16), and that God loves the entire world (John 3:16), but only those who are born again are children of God (John 1:12;11:52;Romans 8:16;1 John 3:1-10).
In Scripture, the lost are never referred to as children of God.Ephesians 2:3 tells us that before we were saved we were “by nature objects of wrath.”Romans 9:8 says that “it is not the natural children who are God's children, but it is the children of the promise who are regarded as Abraham's offspring.” Instead of being born as God’s children, we are born in sin, which separates us from God and aligns us with Satan as God’s enemy (James 4:4;1 John 3:8). Jesus said, “If God were your Father, you would love me, for I came from God and now am here. I have not come on my own; but he sent me” (John 8:42). Then a few verses later in John 8:44, Jesus told the Pharisees that they “belong to your father, the devil, and you want to carry out your father's desire.” The fact that those who are not saved are not children of God is also seen in 1 John 3:10: “This is how we know who the children of God are and who the children of the devil are: Anyone who does not do what is right is not a child of God; nor is anyone who does not love his brother.”
We become children of God when we are saved because we are adopted into God’s family through our relationship with Jesus Christ (Galatians 4:5-6;Ephesians 1:5). ...
Read more: http://www.gotquestions.org/all-God-children.html