First of all- the word “apostle” means simply “one who has been sent.” So in the most general of ways, all who are believers, by virtue of their duty to be witnesses of Christ and of God’s glory, are considered to be “apostles.”
All who are missionaries and are sent out into the field by their local fellowships, are likewise considered to be “apostles.” We are all called to be the light of the world, and a city set on a hill- for all to see, as we testify of God’s goodness in Jesus Christ the Lord- (Mat. 5). Therefore upon the grounds of the great commission (Mark 16:15)- each and every born again child of God is in some sense- an apostle.
When salvation comes to a weary soul, and deliverance has been experienced, the natural and inevitable response of the one saved, is to publish the good news abroad. Observe how Jesus, during the course of his earthly ministry, would send those whom he had delivered, out into their respective communities to tell of the goodness of God: Mk. 5:18-20 ect.
However, with that being said, we must also observe that the aspect of this title as it was applied to Peter as well as Paul- in say- Galatians 2:7, was something altogether different, having been a special and particular office within the Church, originally designated for, and occupied by, the twelve (Jn 6:70; Matt 10:2; 1 Cor. 12:20).
The office of Apostle then, was the highest possible calling within the entire Church, and was an authority that was equally shared among those who held it. This is made perfectly clear in that when giving the order of primacy respecting the offices of the Church (beginning with the very highest) –Paul writes the following: “And God hath set some in the church, first apostles, secondarily prophets, thirdly teachers . . .” (1 Cor. 12:28).
We notice here that Paul wishes to make it very plain that the highest possible office one could have been called to within the Church, was the office of Apostle. And what is more –according to this passage, is that there were no levels of superiority among the Apostles- for the text says, “first Apostle(s)” in the plural form.
Thus Paul- along with Peter himself had in fact occupied the highest possible office within the Church: the office of an Apostle of Jesus Christ. For more scriptural support on the equality of the Apostles see Mk. 9:33-35; Mat. 20:25-28; Gal. 2:6-9; 2 Cor. 11:5; 2 Cor. 12:11.
“And he came to Capernaum : and being in the house he asked them, What was it that ye disputed among yourselves by the way? But they held their peace: for by the way they had disputed among themselves, who should be the greatest. And he sat down, and called the twelve, and saith unto them, If any man desire to be first, the same shall be last of all, and servant of all.” (Mark 9:33-35)
“But Jesus called them unto him, and said, Ye know that the princes of the Gentiles exercise dominion over them, and they that are great exercise authority upon them. But it shall not be so among you: but whosoever will be great among you, let him be your minister; And whosoever will be chief among you, let him be your servant: Even as the Son of man came not to be ministered unto, but to minister, and to give his life a ransom for many.” (Matthew 20:25-28)
“But of these who seemed to be somewhat, (whatsoever they were, it maketh no matter to me: God accepteth no man’s person) for they who seemed to be somewhat in conference added nothing to me: But contrariwise, when they saw that the gospel of the uncircumcision was committed unto me, just as the gospel of the circumcision was unto Peter; (For he that wrought effectually in Peter to the apostleship of the circumcision, the same was mighty in me toward the Gentiles) And when James, Cephas, and John, who seemed to be pillar(s), perceived the grace that was given unto me, they gave to me and Barnabas the right hands of fellowship; that we should go unto the heathen, and they unto the circumcision.” (Galatians 2:6-9)
“For I suppose I am not a whit behind the very chiefest apostle(s)” (2 Corinthians 11:5)
“I am become a fool in glorying; ye have compelled me: for I ought to have been commended of you: for in nothing am I behind the very chiefest apostle(s) though I be nothing.” (2 Corinthians 12:11)
Clearly then- ALL apostles had equal authority- and this cannot be disputed by Scripture. Though many will come up with examples of Jesus’ interaction with Peter in a special way- these examples - though they speak of Jesus’ love for Peter, and for Peter’s competence in leadership- do not and cannot overthrough the explicit force of the passages given above. For one could just as easily make a case equally as strong and convincing - if not stronger and more convincing- for the primacy of Paul.