Gen. 17:9-14 The token of the covenant 

Gen. 17:9 "And God said unto Abraham, Thou shalt keep my covenant therefore, thou, and thy seed after thee in their generations. 10 This is my covenant, which ye shall keep, between me and you and thy seed after thee; Every man child among you shall be circumcised. 11 And ye shall circumcise the flesh of your foreskin; and it shall be a token of the covenant betwixt me and you. 12 And he that is eight days old shall be circumcised among you, every man child in your generations, he that is born in the house, or bought with money of any stranger, which is not of thy seed. 13 He that is born in thy house, and he that is bought with thy money, must needs be circumcised: and my covenant shall be in your flesh for an everlasting covenant. 14 And the uncircumcised man child whose flesh of his foreskin is not circumcised, that soul shall be cut off from his people; he hath broken my covenant. 

God gave unto Abraham and to his seed the ordinance of circumcision.  Circumcision was not the covenant, but was a token of the covenant that God made with Abraham and his descendents.  Circumcision of the male children identified them as being beneficiaries of the covenant of which God had made with Abraham and subsequently with them.  Circumcision was not just for the natural descendants of Abraham, but also the ordinance was to be performed on all that were born in the house or bought with money of a stranger. 

Male children who were the descendants of Abraham were to be circumcised when they were eight days old.  The number eight in the scriptures is associated with the subject of new beginnings.  This natural circumcision of the male children at eight days of age is a type or figure of what happens when the elect child of God is born of the Spirit and undergoes the spiritual circumcision of the heart.  Being born of the Spirit is a new beginning for God's elect.  That natural circumcision of the foreskin is a type or figure of the spiritual circumcision of the elect is set forth for us in the following passages of scripture:

    1.  Rom. 2:28, 29 "For he is not a Jew, which is one outwardly; neither is that circumcision, which is outward in the flesh: But he is a Jew, which is one inwardly; and circumcision is that of the heart, in the spirit, and not in the letter; whose praise is not of men, but of God."

    2.  Col. 2:11-14 "In whom also ye are circumcised with the circumcision made without hands, in putting off the body of the sins of the flesh by the circumcision of Christ: Buried with him in baptism, wherein also ye are risen with him through the faith of the operation of God, who hath raised him from the dead.  And you, being dead in your sins and the uncircumcision of your flesh, hath he quickened together with him, having forgiven you all trespasses; Blotting out the handwriting of ordinances that was against us, which was contrary to us, and took it out of the way, nailing it to his cross;"

These two New Testament passages speak of a spiritual circumcision of the heart.  This is not a fleshly circumcision, but a spiritual circumcision.  The circumcision is not of the foreskin, but of the heart.  Natural circumcision would identify someone who was embraced by the covenant God made unto Abraham and his descendants.  This identity was made by natural eyesight and would be made only concerning the males.  Spiritual circumcision of the heart can be made by identifying the changed life of the individual whose heart has been circumcised.  We do this when we see the fruits of the Spirit manifest in the life of the individual whose heart has been circumcised: Gal. 5:22-23 "But the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith, meekness, temperance: against such there is no law." 

    Natural circumcision was performed only on the males.  Spiritual circumcision of the heart is performed upon all the elect, including both males and females. 

    Natural circumcision was performed by the hands of some man.  Spiritual circumcision is performed by Jesus Christ and is made without hands.  Natural circumcision involved the cutting away of a portion of flesh.  Spiritual circumcision involves the removal of the condemnation of our sins under the law.  Certainly spiritual circumcision far exceeds the effect for good that natural circumcision brought about.  Spiritual circumcision involves a quickening which gives us spiritual life.  This is a new beginning for the child of God.  In addition, spiritual circumcision brings about a new beginning by taking us from a state of condemnation to a state of justification before God. 

Moreover, spiritual circumcision identifies us as having part in the covenant of redemption stated in Rom. 8:29, 30.  When we see the evidences of the spiritual circumcision of our heart we are assured that God chose us before the foundation of the world, that he predestinated us to be conformed to the image of his Son, that he justified us by the blood of Christ, and that we shall be glorified in the resurrection of our bodies. 

"And the uncircumcised man child whose flesh of his foreskin is not circumcised, that soul shall be cut off from his people; he hath broken my covenant."  While it was possible that the descendent of Abraham could be cut off from his people by not being circumcised, yet it is not possible for someone who has had their heart circumcised by the circumcision made without hands to be cut off from the benefits of the covenant of redemption.   

Gen. 17:15-18 The astounding Promise

Gen. 17:15 "And God said unto Abraham, As for Sarai thy wife, thou shalt not call her name Sarai, but Sarah shall her name be. 16 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. 17 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? 18 And Abraham said unto God, O that Ishmael might live before thee!"

According to what we read in the book of Romans, at the time that God appeared unto Abraham both his reproductive ability and Sarah's reproductive ability were dead: Rom. 4:19 "And being not weak in faith, he considered not his own body now dead, when he was about an hundred years old, neither yet the deadness of Sarah's womb:"  According to nature, neither Abraham nor Sarah were capable of having children.  Yet God promised Abraham in the above passage that He would give him a son of Sarah.  The initial reaction of Abraham is exactly what you would expect from someone who did not have the ability to have children anymore and who was married to someone who was way past the time in nature that she could typical conceive a child.  Abraham laughed in his heart at what God told him.  According to nature Abraham knew that this was impossible. 

Abraham and Sarah had 12 years before tried to help the Lord out in bringing to fulfillment the child through which they thought the promise of God would come.  Sarah had given her handmaid Hagar to Abraham to wife and to have a child.  The impatience and doubts of men is manifest in their actions.  Men by nature seem to believe that God needs help.  God never has needed the help of man and he never will need the help of man to bring about his covenant promises. 

Abraham realizing the reproductive deadness of his own body and the deadness of Sarah's womb said unto God "Oh that Ishmael might live before thee."  At this point Abraham is still of a doubtful mind that it could conceivably be possible that he and Sarah could conceive of a son.  However, that would soon change.

God changed the name of Sarai to Sarah.  The name, Sarai, means my princess.  The name, Sarah, means princess of a multitude.  God made it very plain that the promise he had previously made unto Abraham that he would be the father of nations and kings would come out of his bowels was to be fulfilled through Sarah.  He promised that Sarah would be the mother of nations and those kings of peoples would come through her. 

Surely God's ways are not our ways, nor his thoughts, our thoughts.  What is impossible with men are possible with God.