Why is the covenant God makes with Adam not pretty?

Les explains that after Adam and Eve ate, they totally plunged the human race under the curse, and God makes a covenant with Adam. It is not a very pretty covenant because in it He promises all the ramifications of the curse, and everything would come under the curse, including the weeds and thistles and associated things. But in the very center of this covenant is the promise of a Redeemer. In Genesis 3:15 God says He will put enmity between Satan and the woman, and between Satan's seed and her seed. That seed of the woman is Christ, so there would be a running battle between Satan and Christ. The seed of the woman would bruise Satan's head, which He did at the cross, but Satan would bruise His heel, which Satan accomplished when he caused the suffering of Christ at Calvary. From this promise in Genesis 3, that God would provide a Redeemer through the woman, Les teaches that the Abrahamic covenant is built, showing that through Abraham and his offspring the seed of the woman would come.