The Sons of Abraham – Genesis 21:1-21

Abraham Sermon Series - Genesis 21:1-21This sermon is based on Genesis 21:1-21. Click here to read the text.

God always keeps His Word. He promised Sarah and Abraham a son in their old age. Not just any son, but the son of covenant promise. He kept that promise (“as He had said… as He had promised.” v. 1)!

God is powerfully present with and in His people to keep His Word. He “visited” Sarah and caused her to conceive. When the Lord visits His people, powerful deliverance often occurs (see Ruth 1:6; 1 Samuel 2:21). Of course the greatest visits by the Lord to His people are the Incarnation of God the Son in the person of Jesus – in whom salvation was accomplished – and the indwelling presence of the Holy Spirit – by whom salvation is applied to the elect by regeneration.

God is sovereign in bringing His promises at the appointed time (v. 2). Sarah and Abraham waited at least twenty-five years for the birth of Isaac. Abraham’s people would wait 400 years or more to take possession of the land. It would be 2000 years before Jesus would come to accomplish salvation so that there would be spiritual sons and daughters of Abraham from all nations. Though the waiting may seem long by our standards, we know that God is never late, nor is He early. His salvation and His blessings arrive when He intends them according to the fullness of time (Ephesians 1:9-10).

God’s faithfulness is no surprise, but it is always amazing! As such it produces joyful worship in/from those who receive His grace. Sarah “laughed” (Isaac-ed) with joy to the LORD at the birth of Isaac (v. 6). By extension, the grace of God as evidenced in the life of Sarah, and when it is evidenced in the life of others as well, serves as a reason for observers to hear about grace and to join in the joyful praise of God (“… everyone who hears will laugh over me.” v. 6).

God’s faithfulness is not momentary but ongoing. Isaac was born and he continued in life by the provision of God. That provision of safety and health was celebrated at a weaning party.

The joyful celebration of God’s grace by some might prove an occasion for envy, disdain, and mockery for others. So it was with Ishmael who laughed at (mocked, derided) Isaac. Ultimately by mocking God’s chosen heir of the covenant, Ishmael was deriding God and His sovereign plan of grace. Those who are in Christ can expect to be mocked, derided, even persecuted. In Galatia, it was the Judaizers who mocked the freedom of the Gospel. They taught that the Gentile converts had to become Jewish (through circumcision, etc.) before they could truly be in Christ. Paul said they were living according to the flesh and as such were more closely associated with Ishmael, the son of a slave-woman, than with Isaac, the son of promise (Galatians 4:21-31). In our own day and time, the more faithful we remain to the Gospel and the word of God the more we can expect to be laughed at by others.

Sovereign grace always wins. God’s eternal, sovereign plan for the covenant to pass through Isaac survived and overcame Sarah’s barrenness, her marriages to pharaoh and Abimelech, Abraham’s disputes with Lot, Abraham’s battle with Chedorlaomer, and the mocking presence of Ishmael. Each of these threats was overcome by the LORD. Abraham’s efforts according to the flesh never proved to be a means of salvation and redemption. Rather, it was God who visited Sarah and opened her womb. It was God who confirmed Isaac as the heir of the covenant (v. 12) while also compassionately providing for Ishmael (v. 13). Our efforts to achieve happiness or to accomplish salvation according to the flesh will always fall short. They ultimately work against the grace of God, which is according to the Spirit. The good news is that God has accomplished salvation in Jesus Christ, which was His plan of sovereign grace from before the foundation of the world (Ephesians 1:3-11). All who are in Christ have been born again according to the Spirit and are counted as the spiritual children of Abraham (Romans 9:6-8; Galatians 3:26, 29; 4:29). Where our best efforts in the flesh fail, Jesus Christ, by His grace, always proves faithful. May we ever trust in Him.

Discuss and Pray – Genesis 21:1-21

  1. In what ways has God proved faithful in your spiritual life?
  2. How has His faithfulness made you “laugh” and to tell the story of His faithfulness so others “laugh over” you?
  3. Have you ever had an “Ishmael” who mocked you because of the Gospel? What was the nature of the mockery? How have you responded? How can/should we respond to those who deride Christ and His Church?
  4. What spiritual comfort do you have in knowing that your salvation has been secure since before the foundations of the world according to the sovereign grace of God? How can/should such comfort encourage you to disciple others and to share the Gospel with the lost?
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