Pope Shenouda III
In the event of our Father Abraham meeting Melchizedek, it is written that Melchizedek "was the priest of God Most High" (Gen.14: 18). How was this priesthood instituted. Who gave Melchizedek the authority to bless Abram and what law made Abram offer Melchizedek the tenths of everything he had (Gen. 14:20)? Thus Melchizedek was considered greater than Abraham (Heb.7: 6,7).
At that time there was no written Law explaining priesthood, its honour, duties and blessing to others. In the previous chapters of Genesis there is no mention whatsoever of the words 'priest' or 'priesthood'. From where did the knowledge of priesthood come except through Tradition?