Abraham nearly sacrificing Isaac can be quite a controversial topic but let’s explore what is happening here. Abraham trusted that God would keep the promise to make a covenant nation of his descendants through his son Isaac, the promised son of his wife Sarah. If God was true to this promise, God couldn’t eliminate Isaac because the covenant couldn’t be fulfilled. Abraham trusted that God would be faithful to the promise, so he went forward with sacrificing him, knowing that Isaac couldn’t be taken forever or God would be a liar and covenant breaker.
According to Hebrews 11:17-19, Abraham believed that if Isaac died, God would raise him from the dead, because the covenant promise had to be fulfilled. However, God provided a substitute sacrifice which is a pattern that repeats in the laws of Israel (Ex 13:1-16, Num 3:40-50), pointing to the ultimate penal substitutionary atonement sacrifice (Hebrews 10:1-14), the messiah himself. This scenario was done so that God would prove he was trustworthy enough to honor the covenant made with Abraham. It was for Abraham to see that he could trust God, and for his descendants and everyone reading the story in the future to know that God is always faithful (2 Tim 2:11-13).
Ex 13:11 (NLT) “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.
Hebrews 10:11 Under the old covenant, the priest stands and ministers before the altar day after day, offering the same sacrifices again and again, which can never take away sins. 12 But our High Priest [Jesus] offered himself to God as a single sacrifice for sins, good for all time. Then he sat down in the place of honor at God’s right hand. 13 There he waits until his enemies are humbled and made a footstool under his feet. 14 For by that one offering he forever made perfect those who are being made holy.
Previously in their relationship, Abraham (then Abram) doubted God would follow through with his promise to give him descendants and make a nation from them as he said in (Gen 12:1-3) and this was shown through Abraham’s actions. The first time he doubted God is when he went to Egypt after a famine. Abraham lied and said Sarah (Sarai at the time) was only his sister instead of his wife out of fear they would kill him and take her (Gen 12:10-13). When the Pharaoh of Egypt asked about her and Abraham lied, he took Sarah because he thought she was available. A bunch of plagues hit the Pharoah and he realized he was about to commit adultery. He gave her back and sent Abraham along his way back to Canaan and paid him in servants, livestock, and goods (Gen 12:14-20).
Abraham did the same to king Abimelech, and it resulted in the same. Abimelech was warned in a dream that she was a wife, and gave her back to Abraham and paid him restitution even though Abraham lied (Gen 20:1-18). Abraham lied and abused his wife out of fear and doubt because he didn’t fully trust that God would follow through and protect him long enough to have a child. By this time Abraham had Ishmael but Ishmael was born out of actions of sexual misconduct towards Hagar (his wife’s servant). God said the promise would be through a child from his wife Sarah (Gen 17:18-22) and so Ishmael was not the promised seed. Therefore God’s promise was still not fulfilled and Abraham had no reason to fear.
If Abraham had trusted God at the start and told the truth about his wife, and those Kings tried to kill him for her, they would have failed. How do I know this? God made a promise to save humanity through the Messiah, and then he promised Abraham that this savior would come from his seed, and God is not a man that he should lie (Num 23:19). Even if God did let him get killed, God would have raised him from the dead, otherwise, God would be a liar because a dead man can’t reproduce. That means Abraham had nothing to fear, and those Kings couldn’t touch him. The moment they tried to kill him, they would have got hit with plagues and nightmares just like did when they tried to sleep with Sarah. God’s promises can’t be broken, so anyone who trusts God to fulfill his promises for their lives can rest assured that they have no reason to fear death if those promises require that they are alive.
Fourteen years before the incident with Abimelech, Sarah showed doubt in God’s promise for Isaac, when she gave her servant Hagar to Abraham and they conceived Ishmael (Gen 16:1-16). Abraham would ultimately have eight sons from three different women, but only one of them was the son of Sarah. Since the promise only applied to the seed of Abraham and Sarah, marked by the name changes in Gen 17, then only Isaac is the promised seed, and God confirms this in Gen 17:15-22. At that time, Abraham still didn’t trust God enough to resist Sarah’s suggestion. She gave in to her own doubts about a promised child from her womb and used her servant to “make” God’s promise happen. Afterward, she regretted it and was annoyed when Hagar flaunted her pregnancy. Sarah abused her to the point Hagar ran away, but God promised to bless Ishmael and take care of her and told her to go back to Sarah. God’s blessing was over all of Abraham’s descendants. but the promise covenant was only for the promised seed, the miracle baby, Isaac.
God gave him another chance to fully trust the promise. God put Abraham in a compromising position by having him sacrifice Isaac. This seemingly contradicts his promise to Abraham. God did this to show that no matter what, the covenant was solid and would not be broken from God’s side. Abraham was 75 years old and married to the same woman his whole adult life when God contacted him. All the years of infertility in a culture that uses fertility idols (Joshua 24:2), yet none of them gave him any results, so Abraham’s faith in deities was likely a bit shaken. On the other hand, God (YHWH), showed him that THIS covenant promise was real, and God kept his end of the promise by substituting Isaac. In addition, as stated above this reveals the Penal Substitutionary Atonement mechanism that allows Jesus to die for our sins in Heb 10:1-14. More on Penal Substitutionary Atonement here.
For the sake of argument, let’s say I have an innumerable sum of wealth. If I entered into an agreement with someone to give them money for the rest of their life and the requirement was that they trusted me with no doubt and they were to only rely only on me for money. This means they had to quit their job and work for me as their only income source. Then before I gave them the first check, they had doubts and got money from other sources like gambling. After they apologized and said confirmed that still wanted in on the agreement, I handed them the in cash. Then as a test to prove that I am trustworthy, I told them to burn it before they got a chance to deposit or spend it. This time they were determined to put complete trust in me no matter what because they want the reward of the agreement. As they are about to burn it, I tell them to stop, thank them for trusting me and let them keep the money, and gave them a contract to sign that legally bound me to provide for them for the rest of their life. This is what God offered Abraham as well as us, an eternal promise to care for us and in return, we follow his instructions and him alone and trust him fully.