Is Abraham's sacrifice of Isaac also a prefiguration of the law for redeeming firstborn sons from God?

Question

Every firstborn son belongs to God and must be redeemed. This law is repeated several times in the Pentateuch. For example:

• Ex 13:11-13:

  ¹¹ “This is what you must do when the Lord fulfills the promise he swore to you and to your ancestors. When he gives you the land where the Canaanites now live, ¹² you must present all firstborn sons and firstborn male animals to the Lord, for they belong to him. ¹³ A firstborn donkey may be bought back from the Lord by presenting a lamb or young goat in its place. But if you do not buy it back, you must break its neck. However, you must buy back every firstborn son.

• Num 18:15-16:

  ¹⁵ “The firstborn of every mother, whether human or animal, that is offered to the Lord will be yours. But you must always redeem your firstborn sons and the firstborn of ceremonially unclean animals. ¹⁶ Redeem them when they are one month old. The redemption price is five pieces of silver ..."

(see more Bible verses here).

I am very much aware that the sacrifice of Isaac story (Gen 22) is commonly seen as Abraham's test of faith, prefiguration of God's sacrifice of His Son, and prefiguration of the obedience of Isaac/Jesus. But does the Bible ever mention that the sacrifice of Isaac is also a prefiguration of this law?

What got me thinking is because of the following parallels:

• Isaac is God's fulfillment of his promise to Abraham (see Ex 13:11)
• Isaac obviously belongs to God since it's only by miracle that Abraham had a descendant (Ex 13:12)
• Isaac is the firstborn of Sarah; Ishmael didn't count since he's of a different mother (Num 18:15)
• Although God provided the lamb to replace Isaac, it can still be seen as redemption (Ex 13:13)

Answer 1

Ex 13:13c

you must buy back every firstborn son.

That is, do not sacrifice your firstborn son. In this episode, Isaac was a prefiguration of Christ dying on the cross. He couldn't be both a prefiguration of redeeming the firstborn and a prefiguration of sacrificing the firstborn.

Jesus the firstborn was sacrificed to redeem the firstborns, secondborns, etc. Isaac was a prefiguration of this sacrifice even though he wasn't actually killed. The deeper significance of this event is to foreshadow Jesus' sacrifice—not redeeming the firstborns.

Answer 2

A few issues that need clarified before you can truly answer this question (some below)

How do you come to the conclusion that Ishmael does not count based on Num 18:15?

Abraham was married to Hagar - as was the customs in them days to have more than one wife especially is a women was barren.

Genesis 16:3 So after Abram had been living in Canaan ten years, Sarai his wife took her Egyptian maidservant Hagar and gave her to her husband to be his wife.

Right of the Firstborn

Deuteronomy 21:15-17 - The Right of the Firstborn 15 If a man has two wives, and he loves one but not the other, and both bear him sons but the firstborn is the son of the wife he does not love, 16 when he wills his property to his sons, he must not give the rights of the firstborn to the son of the wife he loves in preference to his actual firstborn, the son of the wife he does not love. 17 He must acknowledge the son of his unloved wife as the firstborn by giving him a double share of all he has. That son is the first sign of his father’s strength. The right of the firstborn belongs to him.

Genesis 17:20 20) As for Ishmael, I have heard you; behold, I have blessed him and will make him fruitful and multiply him greatly. He shall father twelve princes, and I will make him into a great nation. Genesis 21:13: And also of the son of the bondwoman will I make a nation, because he is thy seed.

Based on your inference of Exodus is Isaac also Gods begotten son as well as Jesus?

Genesis 22:2 states ‘only son Isaac’ however is should be ‘only begotten son’ 'YACHID'

Hebrews 11:17 (ASV) 17 By faith Abraham, when he was tested, offered up Isaac, and he who had received the promises was offering up his only begotten son;