If the first agreement with God had been all right, there would not have been any need for another one.
Does the Law disagree with God's promises? No, it doesn't! If any law could give life to us, we could become acceptable to God by obeying that law.
Even though the Law of Moses says that the priests must be descendants of Levi, those priests cannot make anyone perfect. So there needs to be a priest like Melchizedek, rather than one from the priestly family of Aaron.
In this way a weak and useless command was put aside,
Now Christ has been appointed to serve as a priest in a much better way, and he has given us much assurance of a better agreement.