The reading is from St. Paul's Letter to the Hebrews 5:4-10

BRETHREN, one does not take the honor upon himself, but he is called by God, just as Aaron was. So also Christ did not exalt himself to be made a high priest, but was appointed by him who said to him, "Thou art my Son, today I have begotten thee"; as he says also in another place, "Thou art a priest for ever, after the order of Melchizedek." In the days of his flesh, Jesus offered up prayers and supplications, with loud cries and tears, to him who was able to save him from death, and he was heard for his godly fear. Although he was a Son, he learned obedience through what he suffered; and being made perfect he became the source of eternal salvation to all who obey him, being designated by God a high priest after the order of Melchizedek.