“Are you not the result of my work in the Lord? Even though I may not be an apostle to others, surely I am to you! For you are the seal of my apostleship in the Lord”. 

1 Cor 9:1, 2 NIV 

We judge people by the results of their work. A sports coach is assessed by the success or otherwise of the team he works with. A schoolteacher is evaluated by the exam results of his or her pupils. A business manager is regarded by the profits the firm chalks up. 
When the Corinthian Christians queried Paul’s authority as an apostle, one line of reply was, “The fact that you have come to believe in Jesus as a result of my working with you is itself proof of my genuineness. Your existence as a church of Christ is the seal of my apostleship”. “In ancient days the seal was extremely important. When a cargo of grain or dates or the like was being sent off, the last thing that was done was that the bags and sacks and cases were sealed with a seal to show that the consignment was genuinely what it claimed to be. When a will was made it was sealed with seven seals; and it was not legally valid unless it was produced with the seven seals intact. The seal was the guarantee of genuineness. The very fact of the Corinthian church was the guarantee of Paul’s apostleship” (W. Barclay, The Letters to the Corinthians, p87). 
It needs more than numerical success to vindicate a pastor’s ministry today. The quality of his own life will speak volumes and the spiritual growth of the people under his or her care will say it all. 

Lord, raise up deeply committed pastors, priests and ministers for your church .