This will be the last chapter in which the lives of Abraham and Isaac intersect. In fact, this is Abraham’s death chapter. From now on the focus will be on Isaac, the chosen son and the new head of the covenant family. Though there are no great achievements to speak of concerning Isaac’s life, yet he provides a significant link in the history of redemption. The Jews always referred to their God as the God of Abraham, Isaac, and Jacob (e.g. Gen. 50:24; Ex.3:15; Acts 7:32)
Our text focuses on the continuity of the covenant promises of God to Abraham through Isaac which is then passed on to Jacob, and we shall see this already happening in 25:23. The great doctrine which is addressed in this chapter is the doctrine of divine election. I want to present this doctrine to you in fuller detail my next sermon. Right now I want us to see how the covenant promise is passed on in the midst of challenging family relationships in which we are told that Abraham gave all he have to Isaac. (25:4)
Abraham took another wife (25:1-4).
Following the death of Sarah in Ch. 23, Abraham marries Keturah, whose name means ”wrapped in clouds of incense smoke". She bears him a further 6 sons. The prophecy concerning him becoming the father of many nations is beginning to take shape. I want to draw your attention to one of the sons. One of his sons, whose name is mentioned in verses 2-4 is Midian. His offspring, the Midianites were destined to have a great influence upon Israel. Jacob’s sons because of jealousy will put their brother Joseph into a pit, from where he is rescued by Midianite traders, who in turn sell him to Potiphar, an officer of Pharaoh, in Egypt (37:36). Later we read that Moses sought refuge in Midian following his flight from Egypt (Ex.2:11ff).There he meets and marries Zipporah the daughter of Jethro, a priest of Midian (Ex.2:16-22), and Moses will be greatly helped by his Midianite father-in-law, Jethro. Yet the Midianites will also exert bad influence over the Israelites with the Moabites (Numbers 22:1-41, 25:1-18, 31:1-54) and through them Israel will start to worship false gods, bringing God’s wrath down upon them. Gideon in Judges 6-8 will defeat the Midianite army with an army of only 300 men in a remarkable victory.
Isaac's unique place in God's plan (25:5,6)
With so many brothers, and not forgetting Ishmael (7 in all), we may well ask how things would be when Abraham dies and when the inheritance has to be divided. The Bible leaves us in no uncertainty: “Abraham gave all that he had to Isaac. But to the sons of his concubines, Abraham gave gifts while he was still living. And he sent them away from his son, Isaac, eastward to the land of the east.”
The Lord God who knows all things and who steers all history for the sake of His own glory had determined by His own good pleasure and forethought that Isaac, the son born to Abraham and Sarah, his covenant wife, was going to be the next son of the covenant, inheriting the promises that God had made to Abraham. Remember the opening words of the New Testament? “A record of the genealogy of Jesus Christ the son of David the son of Abraham. Abraham was the father of Isaac, Isaac the father of Jacob . . .” (Matt. 1:1- 2). Isaac occupies a unique place there . There were 7 other male descendants of Abraham, but they are not mentioned there. The covenant promise concerning the seed of the woman who will bruise the serpent’s head and accomplish our redemption shall come through Isaac alone.
In order to deal with potential sibling rivalry, the other sons are sent away to the east country (v.6). That is an interesting comment. Adam and Eve after the fall are sent east of Eden (Gen.3:24). Cain settled east of Eden following the murder of his brother (Gen. 4:16). The people who planned and built the tower of Babel came from the east (Gen. 11:2). Abraham, by the grace of God had been brought from Ur in the east to the promised land. In Gen.24 Abraham warned his servant that under no circumstances was he to take Isaac back to the east – to the place from where God had taken Abraham. Isaac belongs here in Canaan, the Promised Land. Eastward was generally understood to mean, “away from God”.
We thank God that today in this gospel age, God’s covenant blessings are being poured once again into the people of the east and the nations, although the gospel is also fiercely resisted by the people of the east, as is true for the all the nations of the world. It began back in the times of the birth of Jesus. Wise men from the East heard that a remarkable child was to be born and so they came to seek Him and to worship Him (Matt.2:1).
So then, Abraham’s other sons are not sent away empty handed. They are given gifts (we may assume that these were generous gifts) while Abraham was still alive, but while the others are provided for, Isaac alone is the one who is to inherit the land and the covenant promises. Matthew Henry writes:
“These sons of the concubines were sent into the country that lay east from Canaan, and their posterity were called the children of the east, famous for their numbers, Judges 6:5,33. (i.e. the Midianites and the Amalekites) Their great increase was the fruit of the promise made to Abraham, that God would multiply his seed. God, in dispensing his blessings, does as Abraham did common blessings he gives to the children of this world, as to the sons of the bond-woman, but covenant-blessings he reserves for the heirs of promise. All that he has is theirs, for they are his Isaacs, from whom the rest shall be for ever separated”
Common blessings are given by God to every member of the human race, but covenant blessings are given by God to those who are the heirs of the promise. A distinction is made by God between Isaac and his brothers from another mother.
If it were up to Abraham he might have chosen Ishmael (Gen. 17:15-27) in the same way as Isaac would choose Esau over Jacob. God chooses differently to us. He chooses Isaac over Ishmael. He chooses Jacob the younger over Esau the older. He chooses David, the last born of the sons of Jesse. And God chooses, Isaac and Jacob and David, not because they are better men than others. They are not. Read the history of the Bible and you will see this for yourself. No, for His own reasons and for the sake of His own glory and because He loved them He chooses them.
The way to translate that into NT language is this: Have you received Grace from God to become a Christian through believing and trusting in the Lord Jesus with all your heart, soul, mind and strength? Have you entered the new covenant having confessed Him with your mouth and in baptism? Do you appreciate the wonder of the fact that God has given to every Christian believer an unimaginable inheritance, making us joint heirs with Christ? If so then we are the richest people in the world! And the wonder is that none of us has deserved this.No one merits it. No one earns it. It is his unmerited free gift to an undeserving people. “But when the goodness and loving kindness of God our Savior appeared, 5 he saved us, not because of works done by us in righteousness, but according to his own mercy, by the washing of regeneration and renewal of the Holy Spirit” (Titus 3:4,5)
The death and burial of Abraham. (25:7-11)
Abraham lived 175 years. He was 75 years old when he came to Canaan and he lived here for 100 years. He had now lived in Canaan longer than anywhere else.
The words of verse 8 are striking: “Abraham breathed his last and died in a good old age, an old man full of years, and was gathered to his people.” The words speak of a man at peace. It is friendship with God that allows a man to die full of years and satisfied. Matthew Henry again says, “He was full of years, or full of life, including all the conveniences and comforts of life. He did not live till the world was weary of him, but till he was weary of the world he had had enough of it, and desired no more. A good man, though he should not die old, dies full of days, satisfied with living here, and longing to live in a better place”. 
Abraham had the pleasure of seeing Isaac married and settled. And now he could depart in peace. His life, in a sense was complete. God gives a believer that contentment that enables them to enjoy life, but also to be ready to leave it when God calls. The things that made Abraham's life rich was not his possessions, and it wasn't the great age which God had granted him, but rather it was his hope to enter into that heavenly Canaan, the heavenly Jerusalem, the city whose founder and builder was God, whose friendship he had enjoyed in this life. Abraham was gathered to his people. The doctrine of the immortal soul, and of the afterlife comes through here very strongly. Abraham did not cease to be. He was not annihilated. Abraham was gathered to his people. He was gathered to Adam and Eve and Seth and Enoch, and to Noah and to Sarah… He was gathered to his people. Which people will you be gathered to? Will you be gathered to the children of promise, or will you be gathered to the children of this world? It depends upon with whom we find our ultimate fellowship in this life doesn't it?
The Methodist, Adam Clarke wrote a good eulogy of Abraham: “Above all as a man of God, he stands unrivaled; so that under the most exalted and perfect of all dispensations, the Gospel of Jesus Christ, he is proposed and recommended as the model and pattern according to which the faith, obedience, and perseverance of the followers of the Messiah are to be formed. Reader, while you admire the man, do not forget the God that made him so great, so good, and so useful. Even Abraham had nothing but what he had received; from the free unmerited mercy of God proceeded all his excellences; but he was a worker together with God, and therefore did not receive the grace of God in vain. Go thou, believe, love, obey, and persevere in like manner.”
In verse 9 we read that Isaac and Ishmael share in the responsibility of burying their father. They buried him in the cave of Machpelah near Mamre, where Sarah was buried (v.9)... but the final fact remains that God blessed Abraham’s son Isaac.
V.11 After the funeral is over God confirms the covenant blessings upon Isaac. Isaac goes and lives at Beer-lahai-roi where God had first taken care of Hagar and Ishmael, and the place where Isaac first saw and met Rebekah, his wife.
At the close of our text Ishmael and his offspring receive a brief mentioning. He became rich and famous. He had twelve sons who were princes and nations (v.16). Today they are the various Arabic people of the Middle East. They lived on the fringes of the Promised Land. They have been touched by the word of God. They believe in the scriptures, but it is one thing to be near the covenant of grace; it is another thing to be in the covenant of grace To this day they remain strangers to the covenant and its promises. Many that are strangers to the covenants of promise are blessed with outward prosperity for the sake of their godly ancestors. Wealth and riches shall be in their house.” But the main question is this. Are you, like Isaac, a son of the covenant, having entered the narrow gate through Christ? For it is in Christ that we, like Isaac inherit all the covenant promises ... the resurrection of our bodies, eternal life in heaven, our heavenly Canaan, for God has promised us all these thing in Christ, the Mediator of a better covenant.
 There is disagreement among commentators as to whether Abraham had taken Keturah as a concubine whilst he was married to Sarah ( In 1 Chronicles 1:32 she is mentioned as his concubine)
 H.C. Leupold: Genesis http://www.ccel.org/ccel/leupold/genesis.xxvii.html
 Matthew Henry’s Commentary : https://www.studylight.org/commentaries/mhm/genesis-25.html
 Matthew Henry : https://www.studylight.org/commentaries/mhm/genesis-25.html
 Matthew Henry : https://www.studylight.org/commentaries/mhm/genesis-25.html