priesthood of all believers
The teaching that every believer is a priest; therefore all believers have direct access to God without an earthly mediator, and are called to praise him and do good works as sacrifices to him.

• From scripture:

…[Y]ou yourselves like living stones are being built up as a spiritual house, to be a holy priesthood, to offer spiritual sacrifices acceptable to God through Jesus Christ. (1 Peter 2:5 ESV)

But you are a chosen race, a royal priesthood, a holy nation, a people for his own possession, that you may proclaim the excellencies of him who called you out of darkness into his marvelous light. (1 Peter 2:9 ESV)

…so that through the church the manifold wisdom of God might now be made known to the rulers and authorities in the heavenly places. (Ephesians 3:10 ESV)

• From The Second Helvetic Confession, Chapter XVIII:

  PRIESTHOOD OF ALL BELIEVERS. To be sure, Christ’s apostles call all who believe in Christ “priests,” but not on account of an office, but because, all the faithful having been made kings and priests, we are able to offer up a spiritual sacrifices to God through Christ (Ex. 19:6; I Peter 2:9; Rev. 1:6). … [T]he priesthood, as we have just said, is common to all Christians….

• From The MacArthur Study Bible Notes on 1 Peter 2:5:

  OT priests and NT believer-priests share a number of characteristics: 1) priesthood is an elect privilege (Ex. 28:1; John 15:16); 2) priests are cleansed of sins (Lev. 8:6–36; Titus 2:14); 3) priests are clothed for service (1 Pet. 5:5; Ex. 28:42; Lev. 8:7ff.; Ps. 132:9, 16); 4) priests are anointed for service (Lev. 8:12, 30; 1 John 2:20, 27); 5) priests are prepared for service (Lev. 8:33; 9:4, 23; Gal. 1:16; 1 Tim. 3:6); 6) priests are ordained to obedience (1 Pet. 2:4; Lev. 10:1ff.); 7) priests are to honor the word of God (1 Pet. 2:2; Mal. 2:7); 8) priests are to walk with God (Mal. 2:6; Gal. 5:16, 25); 9) priests are to impact sinners (Mal. 2:6; Gal. 6:1); and 10) priests are messengers of God (Mal. 2:7; Matt. 28:19–20). The main privilege of a priest, however, is access to God.