It is the Spirit of sonship whereby we become His children, and may call Him "Father."
The church of God is the household of God—composed of God's children. We do not become His children until we are spiritually born—until we receive His Spirit, which is, His nature and life. When we receive His Spirit we are automatically put into His family—His church. Joining one of the social clubs called churches does not put us into God's church!
