Andronicus & Junia, Rm 16.7 (here some translations say “outstanding among (en) the apostles” and others “outstanding to, or in the eyes of, the apostles”. The grammar is en followed by “ho” translating “the” in the dative case. Of this Kittle writes, “en with the Personal Dative. This is a more difficult use. The spatial sense is basic, but other senses, e.g., the instrumental, exert an influence. With Persons in General. a. With a name in quotations, en denotes the author (Mk. 1:2) or a character (Rom. 11:2). b. With the plural or collective singular it means “among,” as in Rom. 1:12; Gal. 1:16.). [Gerhard Kittel, Gerhard Friedrich, and Geoffrey William Bromiley, Theological Dictionary of the New Testament, Abridged in One Volume (Grand Rapids, MI: W.B. Eerdmans, 1985), 233.]
James saw the risen Christ, 1 Cor 15.7, “Then He appeared to James, then to all the apostles.”
Contact with the risen Christ is one of the required marks of apostolic commissioning, Ac 1.22, 1 Cor 9.1.
Paul called James an apostle, Gal 1.19. YLT, “and other of the apostles I did not see, except James, the brother of the Lord.”
James functioned with apostolic authority.
Ac 12.17 Peter directed news of his release be reported to James specifically.
Ac 15 James gives the decisive judgment at the Jerusalem council
Ac 21.18 Paul treats James as the central Jerusalem authority
Gal 2.9 Paul calls James a “pillar” of the church alongside Peter and John
Early church writers recognized James “apostlic”, e.g. as having and exercising the authority and religious leadership indicative of apostles.
Hegesippus (2d century), ““James, the brother of the Lord, succeeded to the government of the Church in conjunction with the apostles… He was called the Just by all from the time of our Savior to the present day… He alone was permitted to enter into the Holy Place… Because of his surpassing righteousness he was called the Just and Oblias, which signifies in Greek ‘Bulwark of the people’ and ‘Righteousness.’”
Clement of Alexandria (quoted by Eusebius’ Ecclesiastical History), “Peter and James and John, after the ascension of the Savior, though they had been preferred by the Lord, did not contend for honor, but chose James the Just, the brother of the Lord, to be bishop of Jerusalem.”
Eusebius (4th century), “So remarkable a person as James was, and so universally esteemed for righteousness, that the more sensible even of the Jews were of the opinion that this was the cause of the siege of Jerusalem… These things are recorded at length by Hegesippus.”