|The Twelve Apostles|
When asking if the expression ‘apostolic church’ refers to the church’s missional nature, one must understand the expression in its historical context. Clearly the use of ‘apostolic church’ (ἀποστολικὴν ἐκκλησίαν) in the Nicene-Constantinopolitan Creed of 381 referred to the church that continued from Jesus and the Twelve to that day. In early Christianity, the Twelve were the first bearers of the message and teachings of Jesus and they in turn sent other messengers with this message. The pattern is heard in Paul’s statement to Timothy: “You then, my child, be strengthened by the grace that is in Christ Jesus, and what you have heard from me in the presence of many witnesses entrust to faithful men who will be able to teach others also,” (2 Tim. 2:1-2).
The “one holy catholic and apostolic church” in the fourth century referred to the authentic and authoritative church that continued from Jesus and the apostles, and faithfully transmitted their teaching—the teaching of the apostles that was later canonized in the NT writings. With the rise of Gnostic texts by the second century that claimed apostolic authorship, and by the fourth century as heretical doctrines of Arius were spreading, it became necessary to draw up lists of bishops that could be traced back to the Twelve. As J. N. D. Kelly says, when Christians inserted the title ‘apostolic church’ into the Nicene Creed, they wanted to affirm the historic and verifiable continuity of the faith of the church. The emphasis was on the teaching derived from the apostles and the inherent authority therein.
Although ‘apostolic’ did not refer at the time explicitly to missionality it did so implicitly by the church’s connection to Jesus and the apostles. J. F. Torrance states:
The one, holy, catholic and apostolic Church is the Church continuously occupied with the interpretation, exposition and application of the Holy Scripture, for it is in that way that the Church opens its mind and life to the direction and correction of the Word of God. And that was precisely what the Church was doing, not least in the theologically turbulent years between the Nicene [AD 325] and the Constantinopolitan Councils [AD 381]. I refer to the constant exegetical activity undertaken by the Church fathers in their attempt to bring to consistent expression the internal connections of the Gospel and thus, not only to clarify and defend the apostolic and catholic faith in the face of heretical disruption, but to provide the Church with a structural framework within which its members could meditate upon the Holy Scriptures, worship the Holy Trinity, proclaim the Gospel of forgiveness, reconciliation and sanctification, and so fulfill its mission in obedience to the command of Christ.
Indeed, it is on this account only that they will be able to deem themselves apostolic, as being the offspring of apostolic churches. Every sort of thing must necessarily revert to its original classification. Therefore the churches, although they are so many and so great, comprise but one primitive church, founded by the apostles, from which they all spring. In this way all are primitive, and all are apostolic while they are all proved to be one, in unbroken unity, by their peaceful communion, and title of brotherhood and bond of hospitality…
From this statement, Tertullian goes on to qualify what constitutes apostolic churches. They are founded on the facts that Jesus Christ sent the apostles to preach and what they preached was the gospel. This gospel message was received by the apostolic churches from their preaching (vive voce, living voice) and subsequently by their epistles. Tertullian claimed:
If, then, these things are so, it is in the same degree made known that all doctrine agrees with the apostolic churches—those original formations and sources of the faith must be reckoned for truth, as undoubtedly containing that which the very churches received from the apostles, the apostles from Christ, Christ from God. Whereas all doctrine must be prejudged as false that tastes like anything contrary to the truth of the churches and apostles of Christ and God.
With this foundation Tertullian and others were able to judge any teaching as orthodox or heretical by comparing it to the teaching of the apostles. If it was different—heterodox – then its author was “neither an apostle nor an apostolic man; because, as the apostles would never have taught things that were self-contradictory.”
Interestingly Tertullian went on to state: “…those churches who although they do not derive their founder from apostles or apostolic men as being of much later date, for they are in fact being founded daily, yet, since they agree in the same faith, they are considered no less apostolic because they are agreed in doctrine.” In other words, Tertullian affirmed that any church which arises without a direct tie to an eminent bishop or one of the Twelve was no less apostolic if it held to the same teaching as the apostolic churches. For Tertullian, apostolicity was orthodoxy. However, orthodoxy originated in Jesus who commissioned the apostles as “the sent” in order to “go and teach all nations.”
This raises questions about authority, orthodoxy, and missionality. As Tertullian claimed authority is derived from apostolic teaching. Thus, someone in a line of ordained bishops could be disqualified from ecclesial authority when deviating from apostolic teaching. Such heresy would cancel his authority among the apostolic churches. This would apply equally to those who were missional but not orthodox.
A case in point is Ulfilas, the fourth century missionary who evangelized the Goths and translated the Bible into a Germanic language. Ulfilas was consecrated bishop of the Gothic Christians by Eusebius of Nicomedia, bishop of Constantinople and follower of Arius who taught the heretical doctrine that Jesus the Son was neither equal with God the Father nor eternal.  Uflilas held to this Arian teaching as well. Clearly he was missional. He proclaimed the gospel in word and deed. His missional activity led him, as some historians report, to aid 375 persecuted Christian Goths to cross the Danube into Roman territory. Even though he labored to create the Gothic church among Visigoths and other Germanic peoples, because of his Arian heresy, he was not apostolic in his doctrine.
Thus, apostolicity requires not merely missionality but orthodoxy. Both are necessary. Missionality must be orthodox in its formulations and orthodoxy must lead to orthopraxy—going, loving one’s neighbor, and making disciples, in the way of Jesus and the apostles. In the final analysis, apostolicity refers foremost to the church’s grounding in the Scriptures, especially in the teaching of the apostles—the NT—but nevertheless, “… a community of the word is a community engaged in the movement that engaged the apostles.”  The church exists “by the ongoing work and word of the apostles.” For Christians, this means taking part in the movement that engaged Jesus and the Twelve. In summary, J. F. Torrance states:
In its simplest sense the apostolicity of the Church refers back to the original foundation of the Church once for all laid by Christ upon the apostles, (Matt. 7:5; 1 Cor. 3:10ff; Eph. 2:20f; cf. Matt. 16:13-23; 1 Pet. 2:4-9) but it also refers to the interpretation of the existence and mission of the Church in its unswerving fidelity to that apostolic foundation. As the incarnate Son of the Father, Jesus regarded himself as having been anointed by the Spirit and clothed with his power for the fulfillment of his unique evangelical mission. (Luke 4:18f.). With its completion in the cross and resurrection, he commissioned his disciples as apostles to act in his name, thereby linking their subordinate mission with his own supreme mission: ‘As the Father has sent me, so I send you.’ At the same time he breathed his Spirit upon them, thereby constituting their sending by him as the empirical counterpart to the sending of the Holy Spirit by the Father in the name of the Son, which took place as Jesus had promised on the day of Pentecost (John 17:18; 20:21; cf. 14:25f; 16:12; Lk. 24:49; Acts 2:2-8). Jesus was the Apostle in the absolute sense. (Heb. 3:1). The apostles, however, were sent out by him as his chosen witnesses whose word he promised to empower as his own, and thus to unfold in them his own self-revelation. That was the peculiar function of the apostles, to be the link between Christ and the Church, the hinge on which the incarnational revelation objectively given in Christ was grounded and realized within the continuing membership of the Church. The apostolate was designed and formed by Christ to be the nucleus of the Church corporate with himself which his own self-witness was integrated with inspired witness to him and translated into the appropriate form ( i. e. the New Testament Scriptures) for its communication in history. 
The message and mission of Jesus Christ is entrusted to his disciples who are called to be faithful witnesses, from the original Twelve to those who will take their place in the mission of announcing the kingdom of God and holding fast to the faith once for all delivered to the saints.
 Joseph Cardinal Ratzinger, Principles of Catholic Theology, trans. Sister Mary Frances McCarthy (San Francisco: Ignatius, 1987), in Stanley J. Grenz, Theology for the Community of God (Grand Rapids: Eerdmans, 2000), 468; Angelo Di Bernardino, Ancient Christian Doctrine 5: We Believe in the One Holy Catholic and Apostolic Church (Downers Grove, Ill: IVP Academic, 2010), 56. Francis A. Sullivan, From Apostles to Bishops: The Development of the Episcopacy in the Early Church”, 155.
 J. N. D. Kelly, “Catholiqué et ‘Apostliqué aux premiers siècles,” Istine (1969): 33-45, in Bernardino, 56.
 Thomas F. Torrance, Trinitarian Faith: The Evangelical Theology of the Ancient Catholic Faith (Edinburgh: T&T Clark, 2000), 288.
 Prescriptions Against Heretics 20. (ANF 3:252) in Bernardino, 82.
 Ibid., 83.
 Hendrikus Berkof, Christian Faith, trans. Sierd Woudstra (Grand Rapids: Eerdmans, 1979), 409, in Grenz, 468-470.
 Everett Ferguson, ed. Encyclopedia of Early Christianity, Vol. 1 (New York: Routledge Press, 1990), 1149.
 John G. Flett, The Witness of God: The Trinity, Missio Dei, Karl Barth, and the Nature of Christian Community (Grand Rapids: Eerdmans, 2010), 263.
 Ibid., 264.
 Torrance, 285-286.