Genesis 21:1-7

Talks for Growing Christians

Isaac, the Promised Son, is Born

Genesis 21:1-7

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Lesson Number 44

Background Notes

Doctrinal Point(s)

  1. God fulfills His perfect word in His time.
  2. God sees our imperfect faith in His grace.

Practical Application

  1. Remember that your strength will equal your days.
  2. Let’s laugh with God and not at God.


  1. Was Isaac, the promised son, conceived in the natural way?
  2. Does God deliver what He promises?
  3. How is God’s grace shown in the birth of Isaac?
  4. Refer to Deuteronomy 33:25b. What promise did God make to the tribe of Asher? How was Sarah an illustration of this promise? Can this promise be applied to us?
  5. Concerning the promise of Isaac, who laughed?


  1. Yes, but it was obvious that God had worked a miracle. Sarah’s ninety year old body was not only rejuvenated. She was even enabled to nurse the child. See Genesis 21:7.
  2. Yes, always. However, God’s time may differ from what we consider to be the right time.
  3. Sarah laughed and doubted God. However, she had a genuine faith, albeit weak and immature and imperfect. God in His grace not only tolerated this kind of faith, but He strengthened it to the point where God Himself could inspire the writer of Hebrews to write, “Sarah, by faith...”
  4. As your days, so shall your strength be.” The Lord gave Sarah the bodily strength and stamina to carry a child and give birth at an old age. Yes, God will give you the strength to do what He calls you to do.
  5. Abraham laughed, although it is supposed that this was an “it’s-too-good-to-be-true” type of laugh. Sarah laughed in unbelief. God named the child Isaac, which means laughter. Perhaps this was to remind the parents that where there had been the laughter of unbelief, there was now the laughter of joy.


  1. Consider the fact that nothing can deter or thwart God’s sovereign plans for believers. Although these plans may be delayed (according to our timetable), they are not denied. What God has promised, He will do in His prefect time. Do you become impatient thinking that God has missed the right time? Perhaps in His design and timetable, God has included discipline for your impatience. Be encouraged. See Philippians 1:6.
  2. Sarah’s faith was imperfect and immature, but God in His wisdom strengthened it to the point where she became known as a woman of faith. God sees your imperfect and immature faith, but He can strengthen you and cultivate your faith. Let God do this in your life.


  1. Whatever God calls you to do, He will give strength to do it. Sometimes that’s the way the Lord can guide us as to whether we are doing His will or not. There should be no burn out. Check your vision and your attitude. Are you in sync with God’s will for your life?

Key Verses

  • “The Lord did for Abraham and Sarah as He had the set time.” Genesis 21:1-2
  • “Sarah said, ‘God has made me laugh, and all who hear will laugh with me.’” Genesis 21:6

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