Bible Question:
On what basis can Paul's apostolic authority be justified?
Bible Answer:
The most significant validation of Paul’s apostleship comes from the apostle Peter. In 2 Peter 3:1-2 we read,
This is now, beloved, the second letter I am writing to you in which I am stirring up your sincere mind by way of reminder, that you should remember the words spoken beforehand by the holy prophets and the commandment of the Lord and Savior spoken by your apostles. (NASB) 2 Peter 3:1-2
Peter says that he wrote this book to remind us of the words spoken by the holy prophets and the commandments of the Lord as spoken by the apostles. Then he continues talking about future things written by prophets of old. Finally, he concludes the section by referring to Paul. He now says that Paul wrote scripture also (2 Peter 3:15-17). In fact, Peter says that Paul wrote some things that are hard to understand. Peter included Paul along with the prophets and apostles.
It is clear that Paul is an apostle when we read his letters and realize the oother apostles accepted the very letters Paul wrote in which he states repeatedly that he was an apostle in the opening verse of many of his epistles (Romans 1:1; 1 Corinthians 1:1; 2 Corinthians 1:1; Galatians 1:1; Ephesians 1:1; Colossians 1:1; 1 Timothy 1:1; 2 Timothy 1:1; Titus 1:1).
Conclusion:
It is important to remember that all of Scripture is written under the inspiration and authorship of the Holy Spirit. Paul was an apostle because the Holy Spirit repeatedly said he was.