Children have certain privileges or “rights” in their relationship with their parents. A child wouldn’t expect a total stranger to help them with their math homework, but asking that of their parents is not an unreasonable request. This is what Paul is getting at in Galatians 4:7. There are special benefits rooted in a relationship with God when he is your heavenly Father. When we think about our identity in Christ, we need to understand that we are children of God. He loves us, will take care of us, and will provide for us. And we can ask him when we need something, just as a little child will ask their earthly parents.