From apostello; a delegate; specially, an ambassador of the Gospel; officially a commissioner of Christ ("apostle") (with miraculous powers) -- apostle, messenger, he that is sent.

see GREEK apostello

1. a delegate, messenger, one sent forth with orders (Herodotus 1, 21; 5, 38; for שָׁלוּחַ in 1 Kings 14:6 (Alex.); rabbinical שְׁלִיחַ): John 13:16 (where ὁ ἀπόστολος and ὁ πέμψας αὐτόν are contrasted); followed by a genitive, as τῶν ἐκκλησιῶν, 2 Corinthians 8:23; Philippians 2:25; ἀπόστολον ... τῆς ὁμολογίας ἡμῶν the apostle whom we confess, of Christ, God's chief messenger, who has brought the κλῆσις ἀπουρανιος, as compared with Moses, whom the Jews confess, Hebrews 3:1.

2. Specially applied to the twelve disciples whom Christ selected, out of the multitude of his adherents, to be his constant companions and the heralds to proclaim to men the kingdom of God: Matthew 10:1-4; Luke 6:13; Acts 1:26; Revelation 21:14, and often, but nowhere in the Gospel and Epistles of John; ("the word ἀπόστολος occurs 79 times in the N. T., and of these 68 instances are in St. Luke and St. Paul." Lightfoot). With these apostles Paul claimed equality, because through a heavenly intervention he had been appointed by the ascended Christ himself to preach the gospel among the Gentiles, and owed his knowledge of the way of salvation not to man's instruction but to direct revelation from Christ himself, and moreover had evinced his apostolic qualifications by many signal proofs: Galatians 1:1, 11; Galatians 2:8; 1 Corinthians 1:17; 1 Corinthians 9:1; 1 Corinthians 15:8-10; 2 Corinthians 3:2ff; 12:12; 1 Timothy 2:7; 2 Timothy 1:11, cf. Acts 26:12-20. According to Paul, apostles surpassed as well the various other orders of Christian teachers (cf. διδάσκαλος, εὐαγγελιστής, προφήτης), as also the rest of those on whom the special gifts (cf. χάρισμα) of the Holy Spirit had been bestowed, by receiving a richer and more copious conferment of the Spirit: 1 Corinthians 12:28; Ephesians 4:11. Certain false teachers are rated sharply for arrogating to themselves the name and authority of apostles of Christ: 2 Corinthians 11:5, 13; Revelation 2:2.

3. In a broader sense the name is transferred to other eminent Christian teachers; as Barnabas, Acts 14:14, and perhaps also Timothy and Silvanus, 1 Thessalonians 2:7 (6), cf. too Romans 16:7 (?). But in Luke 11:49; Ephesians 3:5; Revelation 18:20, 'apostles' is to be taken in the narrower sense. (On the application of the term see especially Lightfoot on Galatians, pp. 92-101; Harnack, on 'Teaching etc. 11, 3 [ET]; cf. BB. DD. under the word)