In this section of Gen. 21, there are three distinct comparisons that can be made which are very instructive for us today.
The Flesh under the Law vs. the Spirit under Grace
When Sarah told Abraham to cast out the bond woman and her son, she did it because Ishmael was mocking Isaac and because Ishmael was not the heir. This episode became an allegory for us revealing the difference in our condition under the law and under grace. We find the allegory explained in Galatians 4: 22-31. Paul contrasts the bond maid and the free woman (v. 22), the flesh and the promise (v. 23), the old covenant and the new covenant (v. 24), Mount Sinai and Mount Zion (v. 24), bondage and freedom (v. 24-26), Hagar and Sarah (v. 25).
What you learn from this picture and comparison is that the works of the law concern bondage, the flesh, and the old covenant with Moses on Mount Sinai, and these are all pictured by Hagar. Salvation, on the other hand, concerns liberty, the new covenant, and Mount Zion (Revelation 14:1-3, Psalm 48:2), and these are all pictured by Sarah. When God made the promise to Abraham in Gen. 17 granting Abraham a seed (v. 7) and land for an everlasting possession (v. 8) as his inheritance, the promise was made before the law, and the law did not change it (Galatians 3:16-18). Likewise, our salvation and inheritance in Christ were given to us by promise and not by the works of the law.
As Ishmael mocked Isaac, so the flesh torments the spirit after you get saved. The only way to win the battle between the flesh and the spirit is to walk in the spirit (Galatians 5:16) and mortify the deeds of the flesh (Romans 8:13). This is pictured by Abraham casting out the bond woman. As much as it grieved Abraham to tell Ishmael to “hit the road,” it grieves us to tell the flesh to “take a hike.” Sometimes the grief of breaking family and religious ties can be so great that a Christian will choose to live in bondage rather than enjoy his liberty in Christ (2 Cor. 3:17).
A Wife’s Good Counsel vs. a Wife’s Bad Counsel
Sarah gave good counsel to Abraham when she told him to cast out Hagar. You know this because the Lord said, “hearken unto her voice,” (v. 12). Sometimes wives give good counsel and sometimes they give bad counsel. The best way to know is to determine, by faith, whether their counsel lines up with the word of God.
Eve’s counsel in Gen. 3:6 was bad (Gen. 2:17). Sarah’s counsel in Gen. 16:2 was bad (Gen. 12:7, 13:16, and 17:16). Jezebel’s counsel in 1 Ki. 21:7 was bad (1 Ki. 21:19, 23). Esther’s counsel in Esther 7:3-6 was good (Gen. 12:3). Pilate’s wife gave good counsel in Matthew 27:19 (Matthew 18:7). The point is a man would be wise to consider his wife’s counsel in the light of God’s word, particularly when he is out of line with God’s word (1 Peter 3:1-7).
The Provisions of Man vs. the Provisions of God
Abraham sent Hagar and Ishmael away with enough bread and water to get them down to Beersheba. But it soon played out. Consequently, Hagar despaired of life and separated herself from Ishmael so she would not have to watch him die. Man’s physical and religious provisions are just like Abraham’s provisions. They are as unsuccessful to give a man eternal life as Abraham’s provisions were to sustain Hagar and Ishmael for any length of time on their journey.
God had to intervene to spare their lives. As soon as he “opened her eyes,” (v. 19), she was able to see the “well of water” that saved them (John 7:37-39). This is just like the time that Jesus dealt with the woman at the well and gave her a drink of some “living water” (John 4:10-14) that saved her life, forever.
So often, God has to let a person get completely to the end of his rope before he is willing to “see” that Jesus Christ is his only hope of life. This truth is clearly pictured by what happened to Hagar and Ishmael after they were cast out. Don’t you worry about getting God’s mercy by works, religion or the law. God’s mercy will come to you as a gift that you must receive or you’ll not have any mercy!