John

"For whosoever shall do the will of God, the same is my brother, and my sister, and mother." (Mark 3:35)
"And he answered and said unto them, My mother and my brethren are these which hear the word of God, and do it." (Luke 8:21)
"For this is the love of God, that we keep his commandments: and his commandments are not grievous." (1 John 5:3)
"If ye love me, keep my commandments." (John 14:15)
Those who of God family - don't practice sin.
Those who of the devil - willfully, consciously, continuously practice sin.