The Abrahamic Covenant
"I will bless those who bless you, and him who dishonors you I will curse, and in you all the families of the earth shall be blessed" (12:3).
Our Creator would have been entirely just to pass all of us by and leave us in our sin when Adam broke the covenant of works in Eden. We did not fulfill the terms of our probation even though we had every advantage in the garden, and we rejected His rightful authority as Lord when we sought to make ourselves the final determiner of right and wrong. Of course, this sin was not without consequences, for we were all cut off from God's blessed presence when we sinned in Adam (Gen. 3:24). Yet the Lord decided to show grace to some, which means that for the elect, this estrangement would not be eternal. Not everyone would feel His just wrath. Some would benefit from the covenant of grace that God enacted to destroy sin and Satan (v. 15). However, all of the benefits of this covenant of grace would not come at once, for they would be progressively revealed and unfolded through several other covenants, the first of which was the covenant of Noah that established a reliable environment in which God could do His work for His people (8:20-22).
The next covenant under the umbrella of the covenant of grace is God's covenant with Abraham. In the Abrahamic covenant, the Lord reveals His grace in a manner that is particularly clear, for unlike Noah, Abraham started out as a pagan. He was called out of paganism (Gen. 12:1; Josh. 24:2) and given promises of a good land, a great nation, a great name, and tremendous blessing for him and, ultimately, for all of the families of the world (Gen. 12:1-3). And all of this was promised before God officially ratified the covenant, changed Abram's name to Abraham, and ordained the visible covenant sign and seal (15; 17).
In Genesis 15, we find the unmistakable revelation that although Abram and his descendants would have covenant obligations, God alone would ultimately ensure the success of His promises. Verse 1 records the point at which the Lord reminded Abram that He was going to give the patriarch a great reward. Abram did not understand how this could be because he had no heir and no one to whom the reward could be passed on (vv. 2-3). But the Lord graciously responded to this doubt, reiterating His promise to give the patriarch descendants that no one would be able to number (vv. 4-5). All that Abram had was God's word of promise, but that was enough. He trusted our Creator, and on account of his faith alone, God declared him righteous (v. 6). As we have seen in our study of Paul's letter to the Romans, it is by faith alone that the Lord declares us righteous today (Gal. 2:15-16).
Coram Deo
Faith demonstrates that justification is the work of God to which we contribute nothing. Justifying faith receives and rests in the Lord's promises through Jesus Christ and nothing else. Abraham was declared righteous because He recognized that the Lord justifies us apart from our efforts. We are justified when we recognize this, that only He can ensure the success of His covenant promises, which He has kept in Christ Jesus our Lord.