1 Corinthians 9:1-2 says this:
1 Am I not an apostle (a special messenger)? Am I not free (unrestrained and exempt from any obligation)? Have I not seen Jesus our Lord? Are you [yourselves] not [the product and proof of] my workmanship in the Lord? 2 Even if I am not considered an apostle (a special messenger) by others, at least I am one to you; for you are the seal (the certificate, the living evidence) of my apostleship in the Lord [confirming and authenticating it]. AMP
Paul was defending his calling a an apostle here because SOME did not receive him as such! One reason some may have felt that way is because Paul, as Saul, HAD persecuted the church up until his encounter with Jesus on the road to Damascus. Others may have felt this way because they "assumed" that it was up to them to fill the spot that Judas left. Notice this in Acts 1:23-26:
23 And they accordingly proposed (nominated) two men, Joseph called Barsabbas, who was surnamed Justus, and Matthias. 24 And they prayed and said, You, Lord, Who know all hearts (their thoughts, passions, desires, appetites, purposes, and endeavors), indicate to us which one of these two You have chosen 25 To take the place in this ministry and receive the position of an apostle, from which Judas fell away and went astray to go to his own place. 26 And they drew lots [between the two], and the lot fell on Matthias; and he was added to and counted with the eleven apostles (special messengers). AMP
Notice that THEY nominated these two men! Then THEY asked the Lord to show them which one of the two that THEY had picked should be the one! After they asked it does NOT say that they spent time in fasting and prayer in order to clearly hear HIS will! They were not YET filled with the Spirit, so they could not even do that! What DID they do? They "cast lots"! That's also known as "drawing straws"! Does that sound Spirit-led to you? I can't say for certain, but these are my thoughts! If you notice, Matthias, the one "chosen" by lots, is not mentioned again in the New Testament! So, what is MY point in sharing all of this? Even though Paul was NOT recognized by many to actually BE an apostle appointed by Jesus, He did the WORK of an apostle! He did what God had called him to do! So many times in ministry people are more concerned with a title rather than the actual calling! Refuse that type of thinking! If GOD wants you called something, HE will see to it! If not, just DO what you were called, set apart and anointed and equipped to do! There are no rewards for names, only for obedience! The obedient usher who prays for the church and shares the Gospel will have the same reward as the obedient apostle who does what THEY are called to do! AMEN! Be all that God has called YOU to be, and pray for everyone else! Here is a new song from Hillsong United called "Up In Arms". BE the one who is sold out to HIM and HIS will!
Shalom in Him!