This new system was established with a solemn oath. Aaron’s descendants became priests without such an oath,
but there was an oath regarding Jesus. For God said to him, “The has taken an oath and will not break his vow: ‘You are a priest forever.’”
References for Hebrews 7:21
Because of this oath, Jesus is the one who guarantees this better covenant with God.
There were 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.
References for Hebrews 7:25
He is the kind of high priest we need because he is holy and blameless, unstained by sin. He has been set apart from sinners and has been given the highest place of honor in heaven.
References for Hebrews 7:26
Unlike those other high priests, he does not need to offer sacrifices every day. They did this for their own sins first and then for the sins of the people. But Jesus did this once for all when he offered himself as the sacrifice for the people’s sins.
The law appointed high priests who were limited by human weakness. But after the law was given, God appointed his Son with an oath, and his Son has been made the perfect High Priest forever.