The Heb. kohen, Gr. hierus, Lat. sacerdos, always denote one who
offers sacrifices.

At first every man was his own priest, and presented his own
sacrifices before God. Afterwards that office devolved on the
head of the family, as in the cases of Noah (Gen. 8:20), Abraham
(12:7; 13:4), Isaac (26:25), Jacob (31:54), and Job (Job 1:5).

The name first occurs as applied to Melchizedek (Gen. 14:18).
Under the Levitical arrangements the office of the priesthood
was limited to the tribe of Levi, and to only one family of that
tribe, the family of Aaron. Certain laws respecting the
qualifications of priests are given in Lev. 21:16-23. There are
ordinances also regarding the priests' dress (Ex. 28:40-43) and
the manner of their consecration to the office (29:1-37).

Their duties were manifold (Ex. 27:20, 21; 29:38-44; Lev.
6:12; 10:11; 24:8; Num. 10:1-10; Deut. 17:8-13; 33:10; Mal.
2:7). They represented the people before God, and offered the
various sacrifices prescribed in the law.

In the time of David the priests were divided into twenty-four
courses or classes (1 Chr. 24:7-18). This number was retained
after the Captivity (Ezra 2:36-39; Neh. 7:39-42).

"The priests were not distributed over the country, but lived
together in certain cities [forty-eight in number, of which six
were cities of refuge, q.v.], which had been assigned to their
use. From thence they went up by turns to minister in the temple
at Jerusalem. Thus the religious instruction of the people in
the country generally was left to the heads of families, until
the establishment of synagogues, an event which did not take
place till the return from the Captivity, and which was the main
source of the freedom from idolatry that became as marked a
feature of the Jewish people thenceforward as its practice had
been hitherto their great national sin."

The whole priestly system of the Jews was typical. It was a
shadow of which the body is Christ. The priests all prefigured
the great Priest who offered "one sacrifice for sins" "once for
all" (Heb. 10:10, 12). There is now no human priesthood. (See
Epistle to the Hebrews throughout.) The term "priest" is indeed
applied to believers (1 Pet. 2:9; Rev. 1:6), but in these cases
it implies no sacerdotal functions. All true believers are now
"kings and priests unto God." As priests they have free access
into the holiest of all, and offer up the sacrifices of praise
and thanksgiving, and the sacrifices of grateful service from
day to day.