After the people of Israel heard the law from Mount Sinai, they begged Moses to speak to them rather than God, because they would die if they heard the voice of God (Ex 20:19). God knew that no one could behold him in his bare majesty and live (Ex 33:20). And this is why he promised them a Prophet like Moses. God is a consuming fire. But we are sinful mortals.
So God became a man in the person of his Son, just as he had promised when he said that the Seed of the woman would crush the head of the devil (Gen 3:15). We cannot approach God in any other way than through his Son, Jesus Christ, who claimed our flesh as his own, put himself under the same law given in thunder and terror on Mount Sinai, and suffered the torment and punishment we deserved.
The people of Israel said this after hearing the Ten Commandments proclaimed from Mount Sinai. The law revealed the curse of their hearts, and it struck terror into them. As Moses said to them, God is testing you so that you do not sin. In other words, God is afflicting you so that you might repent. This is the chief function of the law. But this is not God’s chief function. That is why while he sent Moses to give the law, he would reveal his pure grace and truth through Jesus Christ (John 1:17). God’s proper work is to show mercy. But his love must be fulfilled. So this new Prophet would not abolish the law, but he would fulfill it (Matt 5:17). He would reveal himself to be the very God who not only gave them the law in loud thunder, but also fed them with the sweet manna in the wilderness.
Jesus reveals himself to be the Prophet spoken of by Moses when he feeds the five thousand. Here is God in the flesh, helping and showing mercy on his unworthy creatures. He is not an earthly king or lawgiver. He is much greater than these. His reign excels that of earthly kings who can only rule the body, and his works are greater than prophets who only give the law. He fulfills what all the kings of Judah could only hope in, if they actually feared God. He fulfills what all the prophets foretold when the Spirit gave them utterance. He fulfills all righteousness and salvation, and he thereby rules our hearts and minds with his grace.