God gave his law to show people how they could have a relationship with him.
So the law appointed priests. That shows people that nobody can achieve a right relationship with God by their own efforts. They must have a priest who will speak to God on their behalf. And now, the priest that God has chosen for this purpose is his Son, Jesus.
Also, the law appointed men who were weak to be those priests. They were weak because of the bad and wrong things that are in people’s lives. That shows that everyone has done wrong things against God. But now God has appointed Jesus to be our priest. And he never did anything that God considers wrong (Hebrews 4:15).
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