Genesis 21: “The Lord Visited Sarah”
1. The Fulfilment of Promise
“The Lord visited Sarah as He had said, and the Lord did to Sarah as He had promised. And Sarah conceived and bore Abraham a son in his old age, at the time of which God had spoken to him.” (Gen 21:1–2)
At last, the promise first given in Genesis 12 and confirmed through years of waiting is fulfilled.
Three times the text repeats “as He had said / promised / spoken” — stressing the absolute fidelity of God.
St John Chrysostom comments:
“When God delays, He does not forget. Delay is His preparation for the greater joy.” (Homilies on Genesis XLV)
Sarah’s womb, long barren, becomes the cradle of Israel’s hope.
The miraculous birth prefigures another — the Virgin Birth — in which divine promise again overturns natural limits.
2. The Child of Laughter
“Abraham called the name of his son who was born to him, whom Sarah bore him, Isaac.” (v. 3)
The name Isaac means “he laughs.” Once Sarah laughed in doubt; now she laughs in delight.
“God has made laughter for me; everyone who hears will laugh over me.” (v. 6)
St Ambrose reflects:
“Her laughter is not derision but thanksgiving. For when grace comes, joy breaks forth.” (On Abraham II.8)
This joy is the mark of all who receive divine promise. The true Isaac — Christ — brings laughter restored to a sorrowing world.
3. The Circumcision of Isaac
“Abraham circumcised his son Isaac when he was eight days old, as God had commanded him.” (v. 4)
Abraham obeys precisely. The sign of the covenant is renewed in the new generation.
The Fathers saw here the continuity of faith — promise handed on by obedience.
St Bede notes:
“As Isaac bore the mark of the covenant in his flesh, so the Christian bears in Baptism the sign of Christ’s Passion on the soul.” (Commentary on Genesis, 21)
Obedience confirms joy; grace leads to duty.
4. The Growth of the Child and the Conflict
“The child grew and was weaned, and Abraham made a great feast on the day that Isaac was weaned. But Sarah saw the son of Hagar the Egyptian, whom she had borne to Abraham, mocking.” (vv. 8–9)
Joy and jealousy now meet. Ishmael, perhaps a young man of sixteen, mocks Isaac — echo of Cain’s envy for Abel.
Sarah perceives the threat to the promised line.
St John Chrysostom remarks:
“This was no childish jest, but the contempt of unbelief.” (Homilies on Genesis XLVI)
The old and new covenants cannot coexist as equals; one is born of promise, the other of flesh. Yet the story is not cruelty, but divine pedagogy.
5. The Expulsion of Hagar and Ishmael
“Cast out this bondwoman and her son; for the son of this bondwoman shall not be heir with my son Isaac.” (v. 10)
To modern ears this sounds harsh, but it is a mystery of providence.
St Paul interprets it spiritually:
“The son of the slave was born according to the flesh, the son of the free woman through promise.” (Gal 4:23)
The two mothers symbolise two covenants:
Hagar — Mount Sinai, law, bondage.
Sarah — Jerusalem above, grace, freedom.
St Augustine writes:
“The casting out of Hagar prefigures the ending of the old observances; not that they were evil, but that they were fulfilled.” (City of God XVI.31)
Abraham’s pain is real, yet his obedience is faith’s offering.
6. God’s Mercy to Hagar
“Abraham rose early, took bread and a skin of water, and gave it to Hagar… She departed and wandered in the wilderness of Beersheba.” (vv. 14–15)
When the water runs out and despair closes in, God again intervenes.
“God heard the voice of the boy… and the angel of God called to Hagar from heaven.” (vv. 17–18)
The Lord who sees the outcast in Genesis 16 now hears the cry of her son.
His mercy extends beyond the covenant’s boundaries — yet always in view of the covenant’s purpose: that all nations be blessed through Abraham.
St Bede comments:
“He who promised the child of freedom does not despise the child of the bondwoman. Mercy goes before judgement.” (Homilies on Genesis, 21)
Thus, God shows Himself Father of all, yet faithful first to the order of His promise.
7. The Well of Water
“Then God opened her eyes, and she saw a well of water.” (v. 19)
The well already existed — she had not seen it. So too grace is near to those who despair, though unseen until faith opens the eyes.
St Ambrose writes:
“The fountain was not created but revealed, for the mercy of God is ever present though hidden to the troubled mind.” (On Abraham II.9)
Water here prefigures Baptism: life restored to the dying through divine revelation.
8. Ishmael’s Future
“God was with the boy, and he grew up; he lived in the wilderness and became an expert with the bow.” (v. 20)
Even outside the chosen line, God’s providence continues.
Ishmael’s twelve sons will become princes — another echo of the twelve tribes.
God’s blessing is broader than His covenant, yet His covenant remains the heart of His plan.
St John Chrysostom notes:
“The Lord abandons none of His creatures; even those set aside in mystery are sustained in mercy.” (Homilies on Genesis XLVII)
9. The Covenant at Beersheba
“At that time Abimelech and Phicol… said to Abraham, ‘God is with you in all that you do.’” (v. 22)
The pagan king recognises divine favour upon Abraham.
Here peace replaces past misunderstanding; the patriarch becomes a witness to God among the nations.
Abraham swears an oath and sets apart seven ewe lambs — sign of covenantal peace.
The place is called Beersheba — “well of the oath” or “well of seven”.
St Bede interprets:
“Beersheba, the well of oath, is the Church, where the waters of Baptism seal the covenant of peace.” (Commentary on Genesis, 21)
Faith leads to peace; covenant brings communion.
10. Abraham’s Worship
“Abraham planted a tamarisk tree in Beersheba, and called there on the name of the Lord, the Everlasting God.” (v. 33)
He plants a tree — a sign of rootedness and permanence — and calls upon the Lord, El Olam, “the Everlasting God.”
After years of wandering, the patriarch finds rest in worship.
St Augustine sees here a symbol:
“He plants a tree where he calls upon the Everlasting God; for the Cross is the tree on which we adore eternity made visible.” (City of God XVI.32)
Thus the story ends not with domestic peace alone, but with adoration — faith’s final act.
11. Theological Summary
| Theme | Revelation |
| Isaac’s birth | God’s faithfulness; miraculous fulfilment of promise |
| Laughter of faith | Joy that follows trust in divine timing |
| Hagar and Ishmael | Law and grace, flesh and promise, both under mercy |
| The well of water | Divine providence and Baptismal renewal |
| Covenant at Beersheba | Peace flowing from fidelity |
| The tree and worship | The Cross and adoration of the Eternal God |
St Bede summarises:
“In this one chapter we see the Church foretold: joy of the faithful, mercy to the outcast, and peace established by covenant.” (Commentary on Genesis, 21)
12. Moral and Spiritual Application
Trust God’s timing. His promises are certain, even when delayed.
Rejoice in grace. Faith’s laughter is gratitude, not scepticism.
Obey in trial. True faith acts, even when the heart trembles.
See mercy everywhere. God hears the cry of those outside our expectations.
Worship faithfully. Like Abraham, plant the tree of prayer where God has planted peace.
13. Christ the True Isaac
All Genesis 21 points to Christ:
The miraculous son born by divine promise.
The laughter that conquers despair.
The well of living water opened for the dying.
The tree of covenant, prefiguring the Cross.
St Ambrose proclaims:
“In Isaac’s birth we recognise Christ’s; in Hagar’s thirst we recognise the nations; in the well we recognise the font of life.” (On Abraham II.9)
The Gospel is hidden in the tents of Abraham, already shining towards Bethlehem and Calvary.
14. Closing Prayer
O Lord, Everlasting God,
You fulfilled Your promise to Abraham and Sarah,
bringing forth joy from barrenness and faith from delay.
Teach us to trust in Your timing,
to rejoice in Your mercy,
and to recognise Your providence even in exile and dryness.
May we drink from the well of life,
and call upon Your Name for ever,
through Christ our true Isaac,
who lives and reigns with You in the unity of the Holy Spirit,
one God, world without end. Amen.
St. Mary's, St. John Bosco and St. Edward's 