The Heidelberg Catechism

Lord's Day 13

Q&A 33

Q: Why is he called God's "only Son" when we also are God's children?

A: Because Christ alone is the eternal, natural Son of God.1
We, however, are adopted children of God-
adopted by grace through Christ.2

1 John 1:1-3, 14, 18; Heb. 1
2 John 1:12; Rom. 8:14-17; Eph. 1:5-6