In the New Testament, the concept of an adoption is found in various places. This is not necessarily in a physical sense, but rather a spiritual one. It might be beneficial to see such verses all in one place. May we all be encouraged by our adoption as children of God!
For ye have not received the spirit of bondage again to fear; but ye have received the Spirit of adoption, whereby we cry, Abba, Father. (Rom. 8:15)
And not only [they], but ourselves also, which have the firstfruits of the Spirit, even we ourselves groan within ourselves, waiting for the adoption, [to wit], the redemption of our body. (Rom. 8:23)
Who are Israelites; to whom [pertaineth] the adoption, and the glory, and the covenants, and the giving of the law, and the service [of God], and the promises; (Rom. 9:4)
To redeem them that were under the law, that we might receive the adoption of sons. (Gal. 4:5)
Having predestinated us unto the adoption of children by Jesus Christ to himself, according to the good pleasure of his will, (Eph. 1:5)