"Adoption" is a new spiritual and moral state of mind, soul, and body of people living according to the commandments of God the Father. "Adoption" is the return of a person from subjection to "Father the devil," that is, to the sinful demands of the flesh, to subjection to "Father God," His Will.  "Adoption" is the process of a person giving up a life of sinful laws and beliefs and beginning to live according to the Will of God.  

"Adoption" in the negative sense is man's rejection of the Will of God the Father, his refusal to follow God's Commandments, his turning to following false teachings, pernicious ideologies, to "demonic" ideas, that is, his submission to "the father of the devil.  

People "adopted" by the "Devil" are "Sons of the Devil", i.e., people who have become involved in opposing the Will of God, i.e., everything that denies the Truth, the Will of God and so have become his opponents.