The Mosaic covenant promised blessing and prosperity. However, it was conditioned upon obedience. When entering into this covenant arrangement, the people of Israel displayed a grossly naive overconfidence with regard to their own ability. Without a thought to the contrary, they assumed that it would not be any trouble for them to keep their side of the bargain. However, despite their promises, they soon joined Adam in deep-seated covenant-breaking rebellion. Indeed, during their travels to the land of Canaan, Israel gave in almost completely to a contemptuous unbelief before God, and so had already forsaken any hope of entering the land as their promised covenant reward. Like Adam, they had failed to enter rest.
Through it all however, God did not cast them off, showing them even at this stage that a promise of grace (Gen 3:15) undergirded the present typological Mosaic arrangement. Eventually, when this Mosaic law had served its function in destroying their false confidence, thereby properly joining them to Adam’s rebellion (and showing them their need for a Saviour); then, the undergirding covenant grace already promised to their forefather Abraham would bloom even further, eventually finding its full expression in the promise of the New Covenant itself. Before the New Covenant Messiah came however, they would have their whole national history (of failure) to look back on in order to prove one simple point: because of their failure to be obedient to God, they were under just condemnation, and had no hope of entering into the promised land of eternal sabbath rest. Only a Saviour, one who had not shared in their sin, could lead them into this promised land. While this truth would become clearer and clearer as they moved towards the New Covenant, already it was being shown to them in picture form. For even at this point, it was only once they had forsaken any right to the land that one of their kinsmen, one who had not shared in their wilderness rebellion, would lead them into the promised land. His name was Joshua, meaning “God saves”. It was the Hebrew equivalent of the name, Jesus.