Priesthood, Priest's Office - Vine's Expository Dictionary of New Testament Words
Priesthood, Priest's Office[ A-1,Noun,G2406, hierateuma ]
denotes a priesthood" (akin to hierateuo, See below), "a body of priests," consisting of all believers, the whole church (not a special order from among them), called "a holy priesthood," 1 Peter 2:5; "a royal priesthood," 1 Peter 2:9; the former term is associated with offering spiritual sacrifices, the latter with the royal dignity of showing forth the Lord's excellencies (RV). In the Sept., Exodus 19:6; Exodus 23:22.
[ A-2,Noun,G2420, hierosune ]
"a priesthood," signifies the office, quality, rank and ministry of "a priest," Hebrews 7:11-Hebrews 7:12, Hebrews 7:24, where the contrasts between the Levitical "priesthood" and that of Christ are set forth. In the Sept., 1 Chronicles 29:22.
[ A-3,Noun,G2405, hierateia ]
"a priesthood," denotes the priest's office, Luke 1:9; Hebrews 7:5, RV, "priest's office."
[ B-1,Verb,G2407, hierateuo ]
signifies "to officiate as a priest," Luke 1:8, "he executed the priest's office."