Is adoption Biblical?
Mordecai adopted Esther. Esther 2:5-7 says, “Now in Shushan the palace there was a certain Jew, whose name was Mordecai, the son of Jair, the son of Shimei, the son of Kish, a Benjamite; Who had been carried away from Jerusalem with the captivity which had been carried away with Jeconiah king of Judah, whom Nebuchadnezzar the king of Babylon had carried away. And he brought up Hadassah, that is, Esther, his uncle’s daughter: for she had neither father nor mother, and the maid was fair and beautiful; whom Mordecai, when her father and mother were dead, TOOK HER FOR HIS OWN DAUGHTER.”
A reference is made to it in Proverbs 29:21, in regard to a man sometimes adopting a servant, “He that delicately bringeth up his servant from a child SHALL HAVE HIM BECOME HIS SON at the length.”
In a sense, we get adopted by God when we get saved. Galatians 4:1-7 says, “Now I say, That the heir, as long as he is a child, differeth nothing from a servant, though he be lord of all; But is under tutors and governors until the time appointed of the father. Even so we, when we were children, were in bondage under the elements of the world: But when the fulness of the time was come, God sent forth his Son, made of a woman, made under the law, To redeem them that were under the law, THAT WE MIGHT RECEIVE THE ADOPTION OF SONS. And because ye are sons, God hath sent forth the Spirit of his Son into your hearts, crying, Abba, Father. Wherefore thou art no more a servant, but a son; and if a son, then an heir of God through Christ.” Also, in Ephesians 1:3-7, “Blessed be the God and Father of our Lord Jesus Christ, who hath blessed us with all spiritual blessings in heavenly places in Christ: According as he hath chosen us in him before the foundation of the world, that we should be holy and without blame before him in love: Having predestinated US UNTO THE ADOPTION OF CHILDREN BY JESUS CHRIST TO HIMSELF, according to the good pleasure of his will, To the praise of the glory of his grace, wherein he hath made us accepted in the beloved. In whom we have redemption through his blood, the forgiveness of sins, according to the riches of his grace.”
Based upon these Scriptures, adoption is Biblical.