Where do Christians get the idea that justification before God is gained by faith and faith alone? The Christian’s faith heritage, as surprising as it might sound at first, is built upon a promise, a simple human response, and a guarantee.

God’s Promise to Abraham

Hundreds of years ago, God made a promise to Abraham.  God promised that He would bless Abraham, that He would allow him to become the father of a great nation and that through him all the nations of the earth would be blessed.

“Now the Lord said unto Abram, Go forth from your country and from your relatives and from your father's house, unto a land that I will show you; And I will make of you a great nation, and I will bless you, and make your name great; and you shall be a blessing. I will bless those who bless you, And I will curse him who curses you; And in you all the families of the earth shall be blessed.” (Genesis 12:1-3)

In order for God to keep His promise to make from Abraham a great nation, He had to give him a son; but Sarah, Abraham’s wife, was barren and Abraham had grown old (Genesis 11:30). 

God waited! Abraham and his wife Sarah grew older and understandably anxious waiting for God to give them a son.  Out of desperation, Abraham dropped a hint to God by reminding Him that he was not getting any younger and that the only heir that he had at that point in his life was Eliezer, his faithful servant. Abraham felt that maybe God would be pleased to substitute Eliezer in the place of the son that He had promised him.

“After these things the word of the Lord came to Abram in a vision, saying 'Do not be afraid, Abram. I am your shield, your exceedingly great reward.' But Abram said, 'Lord God, what will You give me, seeing I go childless, and the heir of my house is Eliezer of Damascus?'“ (Genesis 15:1-2)

God graciously reaffirmed to Abraham that his son would not come from Eliezer, his servant, but from Abraham's own body.

“Then behold, the word of the LORD came to him, saying, ‘This man will not be your heir; but one who will come forth from your own body, he shall be your heir.’” (Genesis 15:4)

In order to encourage Abraham, God gave him an unmistakable sign. He took Abraham outside his tent and told him to look at the stars. He asked Abraham to count all the stars if he could. Abraham knew that it would be impossible because there were so many.

“And He took him outside and said, ‘Now look toward the heaven, and count the stars, if your are able to count them. . .'

Then God made His point—Abraham’s descendants would be too numerous to count.

“And He said to him, ‘So shall your seed be.’” (Genesis 15:5)

Abraham’s Simple Response

If Abraham were to have that many descendants, surely God would have to keep His word and give him a son. Abraham’s response to the Lord became the pattern for all future generations that justification before God comes by faith alone.

“And he believed in the Lord, and He accounted it to him for righteousness.” (Genesis 15:6)

Abraham simply believed in the Lord. The Hebrew word for “believe” is Amen. It means “to lean upon” or “to put trust in.” Abraham placed his trust in the Lord. Notice God’s response to Abraham’s faith. The Lord accounted it (his faith) to him for righteousness.  God declared Abraham to be right before Him based on his faith.

God’s Guarantee

But God did more! He guaranteed His promise. In Old Testament times, personal covenants between human beings were very common and quite binding. The various terms of an agreement were worked out between the parties involved, and when they were agreed upon, the deal was sealed. Once sealed, the terms of the agreement became firmly fixed.

One such binding covenant was a blood covenant. After working out the details of an agreement, the parties involved killed an animal. They would cut the animal in half and walk between the animal pieces.  By this act, they were symbolizing that they would keep the covenant until death.

Once they walked through the animals, the terms were set. Any other parties tampering in any way with the original agreement would be completely out of order. Abraham was familiar with this kind of a covenant.

God recalled again His promise to Abraham, and then he prepared Abraham for a blood covenant.

“And He said to him, ‘I am the LORD who brought you out of Ur of the Chaldeans, to give you this land to possess it.’ He said, ‘O Lord GOD, how may I know that I will possess it?’ So He said to him, ‘Bring Me a three year old heifer, and a three year old female goat, and a three year old ram, and a turtledove, and a young pigeon.’” (Genesis 15:4-9)

Notice the number of animals God asked Abraham to bring.  Abraham must have thought that since God was using so many animals, this was to be a very important covenant.  He was right! God asked Abraham to cut the animals in half.

“Then he brought all these to Him and cut them in two, and laid each half opposite the other; but he did not cut the birds. The birds of prey came down upon the carcasses, and Abram drove them away.” (Genesis 15:10-11)

God then did something totally unexpected. He removed Abraham from actually taking part in the agreement. 

“Now when the sun was going down, a deep sleep fell upon Abram; and behold, terror and great darkness fell upon him.” (Genesis 15:12)

God said that Abraham’s descendants would be strangers in a land that was not theirs, but they would eventually return to the land of promise.

“God said to Abram, ‘Know for certain that your descendants will be strangers in a land that is not theirs, where they will be enslaved and oppressed four hundred years. But I will also judge the nation whom they will serve, and afterward they will come out with many possessions. As for you, you shall go to your fathers in peace; you will be buried at a good old age. Then in the fourth generation they will return here, for the iniquity of the Amorite is not yet complete.’” (Genesis 15:13-16)

God told Abraham that even though he would not actually be there to see the promise kept, it would happen. And God walked between the sacrifices - alone.  Since He alone sealed this covenant, He alone was responsible for its fulfillment.  The fulfillment of the promise no longer depended upon Abraham at all.

“It came about when the sun had set, that it was very dark, and behold, there appeared a smoking oven and a flaming torch which passed between these pieces. On that day the LORD made a covenant with Abram, saying, ‘To your descendants I have given this land, from the river of Egypt as far as the great river, the river Euphrates.’” (Genesis 15:17-18)

Faith Promise Extended to the Nations

I know that many today would respond like this:  “Well, that’s Abraham and that’s the Old Testament written hundreds of years ago.  What does that promise have to do with me today?”

Like Abraham, we also are in need of righteousness before God that we do not have and could never earn.   We have all sinned and come short of the glory of God (Romans 3:23).  The word “sin” means to miss the mark. We have all fallen short of the righteous standard demanded by God.  So how do we receive from God the necessary righteousness?

Several centuries after the original agreement was made, Paul brought up Abraham’s faith promise to the Galatians. Although many of the details of God’s original promise were made specifically to the Jews, Paul said that God’s “faith promise” has been extended to us.

“And the Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel to Abraham beforehand, saying, ‘In you all the nations of the earth will be blessed.’ So then those who are of faith are blessed with believing Abraham.” (Galatians 3:8-9)

“And He did so to make known the riches of His glory upon vessels of mercy, which He prepared beforehand for glory, even us, whom He also called, not from among Jews only, but also from among Gentiles. As He says also in Hosea, “I will call those who were not My people, ‘My people, And her who was not beloved, ‘beloved.’” (Romans 9:23-25)

Believing Gentiles are part of the Gentile nations that would be blessed through Abraham. We are included in Hosea’s prophecy. The blessing is that we receive justification before God based upon faith alone.

God’s Promise Cannot Be Broken

Through the ages of time, there have been many attacks upon justification by faith alone, yet the truth has a tremendous foundation. It remains unshakable because God made the promise and He guaranteed it.

“That the blessing of Abraham might come upon the Gentiles in Christ Jesus, that we might receive the promise of the Spirit through faith. Brethren, I speak in the manner of men: though it is only a man's covenant, yet if it is confirmed, no one annuls or adds to it.” (Galatians 3:14-15)

We live in a sinful world where men often say things that they do not mean. Truth gets lost in the weeds of rhetoric and spin. But God always keeps His word.  Many claim that we must keep the Ten Commandments to be justified. Paul disagreed!  He told the Christians of Galatia that even the Mosaic Law (the Ten Commandments), which came 430 years after God’s original promise to Abraham could not change nor alter in any way the original agreement.

“And this I say, that the Law, which was four hundred and thirty years later, cannot annul the covenant that was confirmed before by God in Christ, that it should make the promise of no effect. For if the inheritance is of the law, it is no longer of promise; but God gave it to Abraham by promise.” (Galatians 3:17-18)

The Object of our Faith

Abraham’s promised son was finally and miraculously given to Abraham and Sarah (Genesis 21).  He came to be by the work of God and the work of God alone. The boy was named Isaac. 

Isaac had a son named Jacob.  Jacob then had a son, and eventually this bloodline led to a man named Jesus Christ.  Jesus was His human name, but He was God in human flesh. Through this promised Seed, the Lord Jesus Christ, God provided the necessary payment for sin, and will fulfill in every detail His promise to Abraham. Paul recognized this, and he wrote:

“Now to Abraham and his Seed were the promises made. He does not say, 'And to seeds,' as of many, but as of one,  'And to your Seed,' who is Christ.” (Galatians 3:16)

Our Faith Heritage Stands Firm

We may appropriate the benefits of Christ’s work on the cross today by faith alone. The foundation upon which we build the truth of salvation by faith alone in Jesus Christ will stand the test of time. It is based upon the promise of God given to a man centuries ago. That man received the promise by faith.  And God Himself guaranteed it.

“What shall we say that Abraham, our forefather according to the flesh, has found? For if Abraham were justified by works, he has something to boast about, but not before God. For what does the scripture say? ‘Abraham believed God, and it was credited to him as righteousness.’ Now to the one who works, his wage is not credited to him as favor, but as what is due. But to the one who does not work, but believes in Him who justifies the ungodly, his faith is credited as righteousness.” (Romans 4:1-5)

“For the promise to Abraham or to his descendents that he would be heir of the world was not through the Law, but through the righteousness of faith. For if those who are of the Law are heirs, faith is made void and the promise is nullified; for the Law brings wrath, but where there is no law, there is also no violation. For this reason it is by faith, in order that it may be in accordance with grace, so that the promise will be guaranteed to all the descendants, not only to those who are of the Law, but also to those who are of the faith of Abraham, who is the father of us all.” (Romans 4:13-16)

New American Standard Bible

New American Standard Concordance; The Lockman Foundation

Bible Knowledge Commentary; New Testament