Upon Adam’s creation God has written His Covenant Law (or Ten Commandments) on Adam’s (and therefore mankind’s) heart in positive terms (Romans 2:14-15). The outward test of this probationary Covenant with Adam was that Adam was not to partake of the fruit of the tree of the knowledge of good and evil. The penalty for disobedience was death, i.e., “In the day you eat of it you shall surely die” Genesis 2:17.
As Scripture attests, Adam, of course, broke the Covenant of Works, e.g., “Like Adam, they have broken the covenant” Hosea 6:7 (NIV). By breaking the Covenant of Works Adam forfeited eternal life (but not his everlasting existence). “For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord” Romans 6:23. Thus, had Adam kept the Covenant of Works, then Adam (and mankind with him) would have received the eternal life that we now have in Jesus Christ who is “the last Adam” (1 Corinthians 15:45).
As God’s replacement-Adam, Jesus Christ kept the Covenant to Works perfectly on behalf of all who the Father has given Him (John 17:12) and received the promised reward (which was life). Therefore when Adam was threatened with death upon breaking his Covenant probation, he was conversely promised life – the eternal life that we receive from Jesus Christ.
Had Adam kept the pre-Fall covenant he would not simply have kept on living as he had been living before he broke the covenant. Thus had Adam not broken the covenant he would have received the bliss and blessings that we have in Jesus Christ, e.g., “Blessed be the God and Father of our Lord Jesus Christ, who has blessed us with every spiritual blessing in heavenly places in Christ” Ephesians 1:3.
The Land flowing with Milk and Honey was merely a token of the bliss and blessings that we have in our new Adam, Jesus Christ. For the covenant promise made to Abraham, the father of believers, was the whole cosmos. E.g., “For the promise that he would be heir of the world was not to Abraham or to his seed through the law, but through the righteousness of faith” Romans 4:13.
Adam, by breaking the Covenant, disqualified mankind from receiving eternal life (i.e., everlasting bliss and blessings) by keeping God’s Covenant Law. However, Jesus Christ is without sin and as such is able to keep the Covenant of Works (and thus receive the life promised in that covenant). Scripture says, “Do this and live,” e.g., “The man who does them shall live by them” Galatians 3:12.
Yes, God was kind and gracious to enter into a Covenant of Works (with the promise of everlasting life upon probationary fulfilment) with Adam as our pre-Fall representative. However, He was even more kind and gracious to enter into a Covenant of Grace with Jesus Christ as our post-Fall representative. Thus the Covenant of Works that condemns us became a Covenant of Grace in which Jesus fulfilled the requirements of the Covenant of Works, and paid the (death) penalty we owed for breaking it.
Jesus is the new Man. It was as a Man that He kept every jot and tittle of God’s Covenant Law. We are saved by His Law-keeping. Therefore it was as a Man that Jesus Christ, the new Adam or Federal or Covenant Head of mankind, saved us.