We are priests, because priests are divinely chosen persons, and so are we. “No man taketh this honour unto himself, but he that is called of God, as was Aaron.” But we have that calling and election; we were all ordained to it from the foundations of the world. We were predestinated to be priests, and in process of time we had a special effectual call, which we could not and did not resist, and which at last so overcame us, that we became at once the priests of God. We are priests, divinely constituted. When we say we are priests, we do not talk as certain parties do, who say they are priests, wishing thereby to arrogate to themselves a distinction. I always have an objection—I must state it strongly—to calling a clergyman, or any man that preaches, a priest. We are no more so than you are. All saints are priests. But, for a man to stand up and say he is a priest, any more than those he preaches to, is a falsehood. I detest the distinction of clergy and laity. I like scriptural priestcraft; for that is the craft or work of the people, who are all priests; but all other priestcraft I abhor. Every saint of the Lord is a priest at God’s altar, and is bound to worship God with the holy incense of prayer and praise. We are priests, each one of us, if we are called by divine grace; for thus we are priests by divine constitution.
From the Metropolitan Tabernacle Pulpit, Volume 1, Sermon 10 by Charles Haddon Spurgeon