Abraham and Sarah were childless and they desperately wanted a son. In those days, a son was the most important asset parents could have. Sons were highly valued because the family name was perpetuated and expanded through the sons. Big families (dynasties) could dominate the land. Big tribes ruled over smaller tribes making large families an economic force, as well as a form of territorial defense.
I am sure Abraham and Sarah loved children and their inability to produce a child made them very sad. Perhaps the heartache that Sarah and Abraham experienced is best understood by parents who have tried and tried, but are unable to have a child. After waiting ten years for God to fulfill His promise to give them a son, Abraham and Sarah agreed that Hagar, Sarah's Egyptian handmaid, could give them a son. So, Abraham slept with Hagar and Ishmael was born when Abraham was 86 years old. For years, Abraham foolishly rationalized that God's promise of a son had been fulfilled with Ishmael's birth. He loved Ishmael with all of his heart and he lavished every good thing upon the lad that he could offer. When Abraham was 99, the Lord appeared to him and Sarah, telling them that against all odds, Sarah would have the promised son in the following year. Sarah laughed at the prophecy, but when Abraham was 100 years old, Isaac was born. Tensions between Hagar/Ishmael and Sarah/Isaac escalated very quickly. Abraham knew he had to do something, but the situation seemed impossible to fix. He loved Ishmael too much to send Hagar and Ishmael away. In fact, I am persuaded that Abraham would not have sent Hagar and Ishmael away from his home if God had not intervened in the family dispute.
"The child[Isaac]grew and was weaned, and on the day Isaac was weaned Abraham held a great feast. But Sarah saw that the[fourteen year old]son whom Hagar the Egyptian had borne to Abraham was mocking, and she said to Abraham, 'Get rid of that slave woman and her son, for that slave woman's son will never share in the inheritance with my son Isaac.' The matter distressed Abraham greatly because it concerned his son[Ishamel]. But God said to him, "Do not be so distressed about the boy and your maidservant. Listen to whatever Sarah tells you, because it is through Isaac that your offspring will be reckoned."(Genesis 21:8-12, insertions mine)
After Hagar and Ishmael were sent away, Abraham and Sarah lived in the land of the Philistines for several years. One day, God came to Abraham and said,"Take your son, your only son, Isaac, whom you love, and go to the region of Moriah. Sacrifice him there as a burnt offering on one of the mountains I will tell you about."(Genesis 22:2) Two things stand out in this verse. First, God called Isaac Abraham's "only son." Why did God say this when Abraham was also Ishmael's father? Evidently, God called Isaac Abraham's "only son" because Isaac was the son of Abraham and Sarah. The point is that God viewed Isaac as the one entitled to the posterity and property of his father. Because God had given Abraham three perpetual covenants, Isaac would be the son through whom those promises would be honored. Consequently, God called Isaac Abraham's "only son."
The second thing that stands out in this verse is that God commanded Abraham to offer Isaac as "a burnt offering" on a mountain. Why did God test Abraham in this fashion? Here are three reasons:
1. God did not command Abraham to kill his son, as in murder, but Isaac was to be presented to God as a burnt offering to atone for Abraham's sin with Hagar. God commanded Abraham to give up his legitimate son (the one through whom the promises would be fulfilled) as a test to see if Abraham loved God more than he loved his only son. Abraham knew that Isaac was the "son of promise." Abraham obeyed the Lord because he believed the Lord would somehow bring a glorious end to this terrible test.
2. God tested Abraham AND Isaac. Isaac's test would be to see if he would be as submissive to God's demands as his father. In other words, God tested Isaac to see if his faith in God was like that of his father. The point to remember is that Abraham had two sons. One child came through the works of the flesh, the other child came through faith. God's children are people of faith like Abraham. Isaac proved his worthiness to be called a son of Abraham because he was willing to submit to the death which God demanded.
3. God used this test on Abraham because He wanted someone to understand His own gift to save man. Furthermore, Abraham, Sarah and Isaac were to be great examples of faith to their offspring. God intended to use the story of Abraham, Sarah and Isaac as a model of Messanic faith for generations to come. Notice how the story of Abraham, Sarah and Isaac parallels circumstances surrounding the birth of Jesus: Sarah's conception was miraculous. Mary's conception was miraculous. The death imposed upon Isaac parallels the death that was imposed upon Jesus. Isaac was willing to die to atone for the sin of his father and Jesus was willing to die "as a burnt offering" in order to redeem sinners. Last, Abraham was willing to give up his only son because God demanded it. Our Heavenly Father was willing to give up His only begotten Son because sin demanded it. Both fathers, Abraham and our Heavenly Father, were willing to sacrifice their greatest treasure to atone for sin. Think about this. The wages of sin is death and the price of atonement for sin is an innocent death. Which is more difficult – giving up your son to atone for sin or receiving the gift that cost God everything He could give? Perhaps this is the question that should be pondered during the Christmas season.