There is a heresy that has been around for a very long time and seems to be gaining traction again especially amongst Christians. It goes something like this:
"We should all be kind and respectful, we should just love everyone because after all, aren't we all God's children?"
Now I agree with the first part but strongly disagree with the latter. Nowhere in Scripture do we see that everyone is a child of God. Nowhere. In fact, just the opposite is true:
Here in John's Gospel, chapter 1 verses 10-13 we see that Christ came into the world yet the world (people) did not recognize Him. He came to His own yet His own did not receive Him. But, to all those who did receive Him (believed) He gave them the right to become children of God. Read verse 13 closely, you have to be born of God to be a child of God and that birth requires believing in Christ. Let's go to John 3:3, where Jesus and Nicodemus are having a discussion and Nicodemus points out that "no one could perfom the miraculous signs you are doing if God were not with him." Look at Christ's response in John 3:3:
What truth do we see here? That unless you are born again (in Christ) you will not see the kingdom of God. Finally, in Matthew's Gospel, in Jesus' teaching from the Sermon on the Mount (Matthew 7:13-14) we see Christ make a bold claim:
Now, if we are all "God's Children" shouldn't we all go to heaven? Yet, here, Christ proclaims that the majority of people will enter the wide gate that leads to destruction. How can this be if we are all Children of God? Simple: we are not. To say otherwise denies the truth of Scripture and makes Christ (God in the flesh) a liar. The appropriate theological term to use when dealing with people is this: "We are all God's creation."
A Child of God is someone who believes on Christ and Christ alone for their salvation and He gives them the right to become a Child of God. The term "We are all God's Children" speaks to a form of Christian Universalism that God will save everyone in the end because of His love for us. That is heresy and is found nowhere in Scripture.
So Christian, please stop using the term "We are all God's chldren" because we are not.