God's Promise Fulfilled

📘 Genesis 21 – The Covenant of Fulfillment: The Birth of Isaac

( “God Keeping Covenant” Series)

Introduction

Genesis 21 is a chapter of joy, fulfillment, and divine faithfulness. After 25 years of waiting… after tears… after doubt… after laughter of unbelief…
the covenant child is finally born.

Isaac’s birth proves that God keeps His covenant in His time, His way, for His glory.

But the chapter also deals with:

• the conflict between Ishmael and Isaac
• Hagar’s distress and God’s mercy
• Abraham’s covenant with Abimelech

This chapter teaches that when God brings promise, He also brings separation, protection, and peace.

Theme: God keeps covenant by fulfilling His promise, protecting His purpose, and providing for His people.

📖 Verse-by-Verse Covenant Insights

Genesis 21:1–2 – God Visits Sarah

“And the LORD visited Sarah as He had said, and the LORD did unto Sarah as He had spoken.”

• God kept His promise exactly as He said.
• Sarah conceived and bore Isaac “at the set time.”

Covenant Lesson:

What God promises, He performs. Delay is not denial.

Illustration:

Like a seed planted in winter that blooms in spring, God’s promises manifest in their season — not before, not after.

Genesis 21:3–7 – Isaac’s Name and Sarah’s Joy

• Abraham names the child Isaac (“laughter”).
• Sarah laughs — not in unbelief this time, but in joy and amazement.

Covenant Lesson:

God turns unbelieving laughter into joyful laughter.

Illustration:

Ever had God answer a prayer so big you had to laugh? That’s Genesis 21 joy — a miracle that makes you smile.

Genesis 21:8–10 – Ishmael Mocks; Sarah Discerns

• At Isaac’s weaning feast, Ishmael mocks Isaac.
• Sarah says, “Cast out this bondwoman and her son.”

Covenant Lesson:

The flesh (Ishmael) always opposes the promise (Isaac). Covenant fulfillment requires separation.

Illustration:

You can’t drive forward looking in the rearview mirror. Old attachments will always fight new blessings.

Genesis 21:11–13 – God Speaks to Abraham

• Abraham is troubled about sending Ishmael away, but God says:

“In Isaac shall your seed be called.”

• God also promises to bless Ishmael, but the covenant line comes through Isaac.

Covenant Lesson:

Not every blessing is covenant. Only the promise child carries the covenant.

Genesis 21:14–16 – Hagar’s Distress in the Wilderness

• Hagar wanders in the desert.
• When the water runs out, she cries and distances herself from Ishmael.

Covenant Lesson:

Even when we are cast out, God still sees and cares.

Illustration:

Like a mother crying in a hospital hallway, God hears the sobs no one else hears.

Genesis 21:17–19 – God Hears the Boy

“Fear not; for God has heard the voice of the lad where he is.”

• God opens her eyes to a well of water.
• Ishmael will become a great nation.

Covenant Lesson:

God provides wells in wilderness places.

Illustration:

Sometimes the answer is right in front of us — we just need God to “open our eyes.”

Genesis 21:20–21 – Ishmael’s Future

• Ishmael becomes an archer and settles in the wilderness of Paran.
• His mother finds him a wife from Egypt.

Covenant Lesson: