I became a Christian through Protestant Christianity and I quickly picked up that one important doctrine was "the priesthood of all believers."
Now I must say that I have given this doctrine very little thought over the twenty-nine years since my conversion. It seems to pop up now and again in conversation when my conversation partner will present it as an obvious truth that some bad person has seen fit to deny but I must confess that it was always a doctrine that loomed small with me.
In part, I suppose that this is because it seems to be built upon two passages of the NT. 1 Peter 2:9 and Rev 5:10.
The idea was that new covenant believers (unlike old covenant Israel) were all priests so we needed no priests (implied: what the flip are those Catholics playing at!!!).
But, of course, 1 Peter 2:9 is actually a quotation from Exodus 19:5–6 in which God calls Israel a kingdom of priests. So the notion of the community as a priesthood is hardly a way of contrasting the old and the new covenants. Old covenant Israel was just as much as "royal priesthood" as new covenant Israel and the nations in Christ.
The idea in crass presentations of the priesthood of all believers (and I am not referring here to the sophisticated presentations) is that in the old covenant the people needed their relationship with God to be mediated by a priest but we no longer do. Mediation is now cast aside.
But it is not.
New covenant believers have no unmediated access to God. We have a new and better mediator—Christ Jesus—but unmediated access we most certainly do not have.
And the other thing that bugged me about the focus on the priesthood of all believers is that, in good Protestant individualist fashion, it was often interpreted as "John is a priest, Jane is a priest, Colin is a priest, Catherine is a priest, ..." and so on. We are all, as individuals, priests. But in both the OT and NT texts it is the community that has a priestly function. The church is a royal priesthood.
And there is the other thing, the idea of the royal priesthood is often interpreted to mean that we now need no mediation in our relationship with God but that is NOT the point of the biblical image. The thing about being a priest is not that you have unmediated access to God but that you mediate in some sense between God and others. So if the church is spoken of as a priesthood then the point is that the church in some sense mediates between God and ... others.
Don't mishear me. I am not saying that we do not have access to God "within the veil"—we have unrivaled access mediated through Christ. My point is simply that the notion of the priesthood of all believers has been misused within some sections of Protestantism.