A discussion of the apostolic church as missional must not overlook the fact that Jesus Christ is too called an apostle. The single verse in the New Testament where apostolos (ἀπόστολος) is used of him is Hebrews 3:1, which says: “consider Jesus, the apostle and high priest of our confession.” In this statement, the author of Hebrews ties apostolicity to the mission of the Triune God (missio Trinitatis). Jesus is the one whom the Father has sent, a theme repeated throughout the Gospel of John. In Hebrews 3:1, the basic idea of Jesus as “the apostle” is about mission.  He was sent by the Father with authority to accomplish a mission that was sacrificial in nature, as 1 John 4:10 states: “[God] loved us and sent (aposteilen) his Son to be the propitiation for our sins.” Thus, the mission of the Triune God led to Jesus’ apostleship. Indeed, his apostleship is the basis of all apostleship. He is “the first apostle, the great apostle, and the source of all apostleship.”  His apostolicity is prior to and the ground of all apostles.After Jesus’ resurrection and ascension, the Eleven sensed the need to replace Judas, and so they sought someone who had been with Jesus and was an eyewitness of the risen Lord. The selection of this twelfth apostle was taken up in order to preserve the mission and authority entrusted to the Twelve. As such, they represented the church as the people of God on the pattern of the twelve tribes of Israel. Luke records in the Acts of the Apostles:
And they put forward two, Joseph called Barsabbas, who was also called Justus, and Matthias. And they prayed and said, “You, Lord, who know the hearts of all, show which one of these two you have chosen to take the place in this ministry (diakonias) and apostleship (apostolēs), from which Judas turned aside to go to his own place.” And they cast lots for them, and the lot fell on Matthias, and he was numbered with the eleven apostles. (Acts 1:23-26)
With Matthias, the Twelve went on to fulfill their purpose as apostles of Jesus. Theirs was a unique and historic role in the establishment of the church—“the household of God, built on the foundation of the apostles and prophets, Christ Jesus himself being the cornerstone,” (Gal. 2:19-20).Although the Twelve were a distinct group, the New Testament describes other apostles. Paul and James, the half-brother of Jesus, are two examples. Paul asks about himself: “Am I not an apostle? Have I not seen Jesus our Lord? Are not you my workmanship in the Lord? If to others I am not an apostle, at least I am to you, for you are the seal of my apostleship in the Lord,” (1 Cor. 9:1-2). As for James, the half-brother of Jesus, Paul said: “But I saw none of the other apostles except James the Lord’s brother,” (Gal. 1:19). Clearly, as with Paul and, probably as with James, the apostolate referred to a group larger than the Twelve.
This idea of an apostolate larger than the Twelve, however, has caused some to question the selection of Matthias, thinking that it was a mistake by the Eleven since Paul was clearly identified as an apostle who would have completed the Twelve. In my Formation Group with students at TEDS, I came across this view in J. I. Packer’s Concise Theology: A Guide to Historic Christian Beliefs that states:
Acts 1:15-26 shows us the church before Pentecost prayerfully asking Christ through the casting of a lot to choose a successor to Judas. Whether they were right to do this, and Paul was Christ’s thirteenth apostle, or whether Paul was Christ’s intended replacement for Judas and the choice of Matthias was a mistake, is not clear in Acts; Luke himself may not have known.”
Of course, Packer does not mention James, the half-brother of Jesus, even though Paul wrote: “I saw none of the other apostles—only James, the Lord’s brother.” Yet, Paul and James each rose to prominence in their respective spheres of leadership among the Twelve. Paul was named the “apostle to the Gentiles” and announced himself as an apostle in most of his epistles (Rom 1:1; 11:13). James, the brother of Jesus, became the leader of the church in Jerusalem and was a principal author of the apostolic decree of Acts 15. Moreover, both leaders are mentioned as eyewitnesses of the risen Lord:
[Jesus] appeared to Cephas [Peter], then to the twelve. Then he appeared to more than five hundred brothers at one time, most of whom are still alive, though some have fallen asleep. Then he appeared to James, then to all the apostles. Last of all, as to one untimely born, he appeared also to me [Paul]. For I am the least of the apostles, unworthy to be called an apostle, because I persecuted the church of God. (1 Cor. 15:7-9)Let us consider Barnabas also. While Luke usually limits his use of apostolos to the Twelve, he does refer to “the apostles Barnabas and Paul” (Acts 14:14). Barnabas co-labored with Paul and was commissioned with him by the Holy Spirit to go to Seleucia and Cyprus (Acts 13:2-4). Paul asked: “Don’t we have the right to take a believing wife along with us, as do the other apostles (οἱ λοιποὶ ἀπόστολοι) and the Lord’s brothers and Cephas? Or is it only Barnabas and I who have no right to refrain from working for a living?” (1 Cor. 9:5-6) Like Paul, Barnabas worked to fulfill the apostolic ministries of proclaiming the gospel and establishing churches. Let us further consider Apollos, Silas, and Timothy. Paul referred to himself and Apollos as apostles (2 Cor. 4:6-9), and to himself, Silas and Timothy as apostles (1 Thess. 1:1; 2:6).
So what does it mean that Jesus is the source of all apostleship? It means that his apostleship as the first apostle sent by the Father for redemptive mission is prior to and the ground all apostleship.
Jesus, The First Apostle
The Twelve Apostles of Jesus
Peter, James and John, Andrew, Philip, Bartholomew, Matthew, Thomas,
James of Alphaeus, Thaddaeus, Simon, Judas Iscariot, and later Matthias
Paul, James the brother of Jesus, Barnabas, Apollos, Titus, Timothy
What does it mean that the church is apostolic? It means that it is “built on the foundation of the apostles and prophets, Christ Jesus himself being the cornerstone,” (Gal. 2:20). It means that the church is sent on mission to continue the missio Trinitatis, doing so through the witness to the gospel of Jesus Christ in word and demonstrated in deed. It means the church is entrusted to guard the deposit of faith—the apostles' teaching recorded in the New Testament—in order to dispense it faithfully to others.If the church is not missional, is it apostolic? Continued.
 Hebrews 3:1, κατανοήσατε τὸν ἀπόστολον καὶ ἀρχιερέα τῆς ὁμολογίας ἡμῶν Ἰησοῦν,
 John 3:17; 34, 5:36; 6:29, 57; 7:29; 8:42; 10:36; 11:42; 17:3, et. al.
 Frank Gaebelein, ed., The Expositors Bible Commentary Vol. 12 (Grand Rapids: Zondervan, 1981): 31.
 Cf. Mark 10:45.
 Philip E. Hughes, A Commentary on the Epistles to the Hebrews (Grand Rapids: William B. Eerdmans, 1977): 127.
 For the Twelve, see: John 6:70 and Rev. 21:14. The New Testament describes other apostles—apostles of the churches as well. Paul states : “And as for our brothers, they are messengers (apostles, ἀπόστολοι) of the churches, the glory of Christ.” 2 Cor. 8:23 While some understand “apostles of the churches” as another category of apostles, it more like means messengers or envoys.
 J. I. Packer, Concise Theology: A Guide to Historic Christian Beliefs (Carol Stream, Ill: Tyndale House, 1993): 197.
 Some doubt whether James, the Lord’s brother, was an apostle, as the ei mē (except, only) of Gal. 1:19 is ambiguous. Colin Brown, New Testament Theology Vol. 1 (Grand Rapids: Zondervan Publ., 1986): 130.
 1 Cor. 15:7, ἔπειτα ὤφθη Ἰακώβῳ, εἶτα τοῖς ἀποστόλοις πᾶσιν.
 See also Acts 13:50–14:4.
 1 Thess. 2:6b δυναμενοι εν βαρει ειναι ως χριστου αποστολοι