As a new prelude to his resumption of one of the key arguments in the book (in chap. 7), the writer stresses God’s complete fidelity to his promises to Abraham, and thus to Israel. Despite certain implications the author will draw from his argument about the priestly order of Melchizedek (see esp. 7:12), God has not changed course, nor have his purposes changed. In the definitive high priest, Jesus, God is bringing to pass his promises to the fathers of Israel. This is an important point to affirm to Jewish Christians who are feeling the pressure of the arguments of nonbelieving Jews.

6:13–14 The custom behind the taking of a vow in the ancient Hebrew culture is indicated in verse 16. God, having no one or nothing greater than himself to swear by, swore by himself. The promise referred to…