That being the case, it follows (i) that any one who has been called by the church to preach the Word, but does not preach it, is in no way a priest; and (ii) that the sacrament of ordination cannot be other than the rite by which the church chooses its preacher. That is how Malachi 2 defines a priest: "The priest's lips should keep knowledge, and they should seek the law at his mouth; for he is the messenger of the Lord of Hosts." ...
Therefore every one who knows that he is a Christian should be fully assured that all of us alike are priests, and that we all have the same authority in regard to the word and the sacraments, although no one has the right to administer them without the consent of the members of his church. ...
A joyful liberty would come back to us, in which we should understand that we are all equal by any law whatever; and, when the oppressive yoke had been cast aside, we should know that he who is a Christian possesses Christ; that he who possesses Christ possesses all things that are Christ's, and is able to do all things."
Martin Luther, Pagan Servitude of the Church (1520) part 6.