That Abraham had two sons, the one by a bondmaid, the other by a free woman.
St. Paul’s outlook and vision
The principle from which he views the Old Testament history may be compared to those lines of light which, on a misty day, open up glimpses among the mountains, in which that which is definitely seen is as nothing to the crowded and mysterious shapes suggested to the imagination. First his mind turns to the tents of the patriarchs, to that simple and pathetic tale--Sarah and Hagar--Isaac and Ishmael. Concentrated in them he sees the spirit of the two covenants. First the Egyptian slave, “which gendereth unto bondage,” “which is Mount Sinai.” But this covenant reminds him of Jerusalem which now is in miserable bondage. But then, high above all, the apostle’s spirit rises to another Jerusalem, where the fetters fall from the soul of every slave that sets foot upon that soil. “Jerusalem which is above is free.” (Bishop Alexander.)
Points of parallelism
Jewish Church.
The bondwoman, Hagar.
Son of the bondwoman, Ishmael.
Natural birth (the flesh).
Mount Sinai.
The Law.
The earthly Jerusalem.
Enslaved.
Fruitful.
Small offspring.
Persecuting.
Expulsion.
The Jewish Church is enslaved.
Christian Church.
The freewoman, Sarah.
Son of the freewoman, Isaac.
Supernatural birth (the promise).
Mount Zion.
The Promise.
The heavenly Jerusalem.
Free.
Barren.
Large offspring.
Persecuted.
Inheritance.
The Christian Church is free.
(W. Sanday, D. D.)
Bond and free
Look at the two covenants as represented by Hagar and Sarah.
I. Their points of connection.
1. They have the same origin. Those who are outside the covenant of promise are still children of the Heavenly Father.
2. They have to a great extent the same elements. Promise on God’s part and conditions on man’s. Ishmael got promises, and Isaac was subjected to conditions. Sinai had its promises; the gospel has its conditions.
3. For a time they largely influence each other. Ishmael and Isaac live together. The law was permeated by the gospel; the gospel by the law.
II. The points of difference.
1. The degrees of prominence in those elements which they possess in common. The covenant becomes under the new dispensation also a testament with large bequests.
2. In the absence or presence of one great vital element--grace, forgiveness.
3. In their effects on men’s natures. The law, like Hagar, bringeth forth children of bondage; the gospel, like Sarah, children of freedom. (Clerical World, 3, 441.)