The doctrine of the priesthood of all believers is commonly accounted a cardinal Reformation position. Thus, I found this quotation from the Venerable Bede (Beda) in his exposition of Revelation 1:6 interesting

Because the King of kings and heavenly Priest united us unto His own body by offering Himself for us, there is not one of the saints who has not spiritually the office of priesthood, in that he is a member of the eternal Priest