Summary: The old preachers used devices called types and the struggle between Ishmael and Isaac is a classic to represent the flesh and the Spirit battling.
Genesis 17:15-19 KJV And God said unto Abraham, As for Sarai thy wife, thou shalt not call her name Sarai, but Sarah shall her name be.  And I will bless her, and give thee a son also of her: yea, I will bless her, and she shall be a mother of nations; kings of people shall be of her.  Then Abraham fell upon his face, and laughed, and said in his heart, Shall a child be born unto him that is an hundred years old? and shall Sarah, that is ninety years old, bear?  And Abraham said unto God, O that Ishmael might live before thee!  And God said, Sarah thy wife shall bear thee a son indeed; and thou shalt call his name Isaac: and I will establish my covenant with him for an everlasting covenant, and with his seed after him.
I. INTRODUCTION—MIRACLES AND MISTAKES
Mistake—A fault in understanding, perception, interpretation. An idea, answer, or act that is wrong. An error. Synonyms: error, fumble, inaccuracy, miscalculation, blunder, confuse, or misunderstanding.
Miracle—An event or action that apparently contradicts scientific laws and is hence thought to be due to supernatural causes. An act of God. A remarkable event. A marvel. Synonyms: A curiosity, mystery, wonder, or an enigma.
We live in a world that is full of mistakes and almost void of miracles. The reason that we live a such a world is merely because of the perception of man. We focus on the mistakes and often fail to see the miracles.
Junius—We lament the mistakes of a good man. . ."
Dwight D. Eisenhower—Nothing is easy in war. Mistakes are always paid for in casualties.
That is the view of fallen man. Mistakes often override the miracles in our lives. When our mistakes are brought to God, He has a way of removing the things that create failure in our spiritual walk. But still there is that often nagging thought of the mistake. Not just an ordinary mistake, but THE MISTAKE.
• The one that embarrassed you.
• The one that ruined your witness.
• The one that caused you to began the downward spiral toward the eddying waters of shame.
-Before long that mistake rules your entire life.
• THE MISTAKE is never far from your mind.
• THE MISTAKE rises and stands before you when you began to pray.
• THE MISTAKE mocks when you lift your hands in worship.
• THE MISTAKE laughs when you volunteer for the prayer shift.
• THE MISTAKE distracts you when you attempt to read the Book.
• THE MISTAKE haunts you every time that you attempt to make a new commitment.
• THE MISTAKE goads you and rides you.
• THE MISTAKE robs your peace.
• THE MISTAKE has raided all of your spiritual reserves.
• THE MISTAKE is something that you can no longer live with.
-Now you live in a place where THE MISTAKE torments you.
If you find yourself in that position, the Word of God has the power to give you the faith to rise up and the Spirit of God is able to provide the deliverance from THE MISTAKE.
II. THE TEXT OF GENESIS
A. General History
The four names mentioned in the text: Abraham, Sarah, Ishmael, and Isaac are no stranger to most of us.
• Abraham, the man that God called out of the land of the Chaldees, the searcher for the city whose builder and maker was God.
• Sarah, the wife of the old patriarch, faithfully followed Abraham into the land that God was going to lead them to.
• Ishmael was the son born to Abraham in his moment of doubt.
• Isaac was the promise that was fulfilled in the old age of Abraham and Sarah.
But there is fair more to the story than just that brief overview.
B. The Origin of the Mistake
When our lives are led into mistakes or failure, whether or not we are willing to admit it or not, that particular failure had began its process long before the capitulation of the act.
There is no greater illustration of this point than to look at the life of Samson.
Judges 15:20-16:1 KJV And he judged Israel in the days of the Philistines twenty years. [16:1] Then went Samson to Gaza, and saw there an harlot, and went in unto her.
For twenty long years that unbridled passion and un-tethered lust ate at the very soul of Samson until it was fulfilled in a single moment of failure.
The same was with the origin of the mistake of Abraham. First of all, Abraham found himself involved in a famine.
Genesis 12:10 KJV And there was a famine in the land: and Abram went down into Egypt to sojourn there; for the famine was grievous in the land.