Apostle
Archimandrite Nikifor’s Biblical Encyclopedia
(Matt. 10:2) (a messenger, one sent) — this word, in the broad sense, is used in Holy Scripture of various messengers of God. Thus the Lord Himself is called the Messenger of God and the Angel of the Covenant (Heb. 3:1; Mal. 3:1), because He was sent by God the Father. In a special sense, however, this name is given to the twelve chosen disciples of the Lord, whom He sent to preach the Gospel. Their names are as follows: Simon, called Peter, and Andrew his brother; James the son of Zebedee, and John his brother; Philip and Bartholomew; Thomas, and Matthew the publican, otherwise called Levi; James the son of Alphaeus, and Simon the Zealot; Judas the son of James, brother of James son of Alphaeus, otherwise called Thaddaeus; and Judas Iscariot, who afterward became the betrayer of the Lord. After the Lord’s Ascension, in place of Judas the traitor, Matthias was chosen by lot and numbered among the apostles (Acts 1:15–26).
The instructions of the Lord Jesus Christ to the apostles are contained in chapter 10 (verses 5–42) of the Gospel of Matthew, and are especially notable for their power and force.