This change has been made very clear since a different priest, who is like Melchizedek has appeared. Jesus became a priest, not by meeting the physical requirement of belonging to the tribe of Levi, but by the power of a life that cannot be destroyed. And the psalmist pointed this out when he prophesied,
“You are a priest forever in the order of Melchizedek.”
Yes, the old requirement about a priesthood was set aside because it was weak and useless. For the law never made anything perfect. But now we have confidence in a better hope, through which we draw near to God.
This new system was established with a solemn oath. Aaron’s descendants because priests without such an oath, but there was another oath regarding Jesus. For God said to Him,
“The Lord has taken an oath and will not break His vow: ‘You are a priest forever.'”
Because of this oath, Jesus is the one how guarantees this better covenant with God.
There are many priests under the old system, for death prevented them from remaining in office. But because Jesus lives forever, His priesthood lasts forever. Therefore He is able, once and forever, to save those who come to God through Him. He lives forever to intercede with God on their behalf. (vv. 25-25, NLT)