Hebrews 5:4-6 Holman Christian Standard Bible (HCSB)
4 No one takes this honor on himself; instead, a person is called by God, just as Aaron was. 5 In the same way, the Messiah did not exalt Himself to become a high priest, but the One who said to Him, You are My Son; today I have become Your Father,[a] 6 also said in another passage, You are a priest forever in the order of Melchizedek.[b]
Hebrews 5:4-6 Amplified Bible (AMP)
4 And besides, one does not appropriate for himself the honor [of being high priest], but he who is called by God, just as Aaron was.
5 So too Christ did not glorify Himself so as to be made a high priest, but He [was exalted and appointed by the One] who said to Him,
“You are My Son,
6 just as He also says in another place,
“You are a priest [appointed] forever