Scripture

Ephesians 1: 4-5
For he chose us in him before the creation of the world to be holy and blameless in his sight. In love he predestined us for adoption to sonship through Jesus Christ, in accordance with his pleasure and will-

James 1:27
Religion that God our Father accepts as pure and faultless is this: to look after orphans and widows in their distress.

Isaiah 1:17 
Learn to do right; seek justice. Defend the oppressed. Take up the cause of the fatherless; please the case of the widow. 

Deuteronomy 10:18 
He executes justice for the orphan and the widow, and shows His love for the alien by giving him food and clothing.

Matthew 25: 45
Truly I say to you, to the extent that you did it to one of the least of these, you did it unto Me.

Galations 4:5-7

To redeem those who were under the law, so that we might receive adoption as sons. And because you are sons, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!” So you are no longer a slave, but a son, and if a son, then an heir through God.

(this is not a conclusive list of scripture regarding the Orphan and Adoption)