Genesis 21 – February 15

The day has finally arrived. The Lord has been promising since Genesis 12 to provide an heir to Abraham through Sarah.

The Miraculous Birth

This is the beginning of a series of miraculous births that occur in Scripture. But, to be clear, there is nothing miraculous about the manner in which Isaac was born. The miracle lies in the fact that he was conceived. Notice that in verse 1, it is the Lord who “did to Sarah as he had promised.” That is to say, it is the Lord who caused her to have the supernatural ability to conceive in her old age. She was able to bear a child, even though she was physiologically incapable. It was a scientific impossibility. 

Later there would be a greater Son of Promise, a child who would fulfill the covenant, who would also be born under miraculous circumstances. The only thing more unlikely than a 90-year-old woman conceiving a child is that a virgin would conceive a child. I believe that the Lord was building an intentional parallel between these two children in order to display that Jesus is the greater child of the promise, the one who would fulfill the entirety of the Abrahamic covenant. 

“The Slave Woman”

It may seem harsh to you and I that the Lord commanded Abraham to send Hagar and her son away. But, don’t neglect the fact that it was also the Lord who provided sustenance for them and caused them to prosper. Abraham did exactly what he should have done, he obeyed God. None of the people in Genesis 21 knew that God was setting up a theological metaphor that would be later presented in the New Testament. The scene of the casting out of “the slave woman” is the central argument found in Galatians chapter 4. Let me provide just a couple of snippets here, but if you have time, go and check out Galatians 4 in its entirety.

“Tell me, you who desire to be under the law, do you not listen to the law?  For it is written that Abraham had two sons, one by a slave woman and one by a free woman. But the son of the slave was born according to the flesh, while the son of the free woman was born through promise. Now this may be interpreted allegorically: these women are two covenants. One is from Mount Sinai, bearing children for slavery; she is Hagar.” (Gal. 4:21-24) 

“But what does the Scripture say? ‘Cast out the slave woman and her son, for the son of the slave woman shall not inherit with the son of the free woman.’ So, brothers, we are not children of the slave but of the free woman.” (Gal. 4:30-31)

What is the point that Paul is making? Hagar represents the attempt to achieve salvation by works. Particularly, Paul is comparing Hagar to the Old Covenant law. Just like Abraham attempted to gain the promise through natural means, when we try to achieve salvation by works, we do not receive the promise. However, when we come to God through the New Covenant, through salvation by grace alone, it is then that we also become children of the promise. “Now you, brothers, like Isaac, are children of promise.” (Gal. 4:28)