You will find several references to adoption in the New Testament, which I don't have in front of me. Basically, our relationship with God through Christ is analogized to adoption.
I was referring the Old Testament but if you want to e-mail me privately when you have time, I'd love to see the New Testament adoptions pointed out. It's easy to miss things ... there is so MUCH in "what is written".
Thank you for pointing that out. I appreciate it.