How do we know that Paul was a true apostle?

Paul's authenticity as an apostle is proven through his dedication to preach the gospel freely, devoid of any financial gain from the congregations he served. This lack of desire for monetary support separated him from false apostles who were motivated by personal gain. By working with his own hands and receiving support from other churches, he eliminated any occasion for false accusers to slander him. The integrity of his message and the sacrificial nature of his ministry, focused solely on the glory of Christ, confirm his apostolic authority. True apostleship is demonstrated through faithful service, clear gospel proclamation, and the avoidance of scandal in ministry.