Luther, from his Commentary on Galatians:
The trouble with these seekers after glory is that they never stop to consider whether their ministry is straightforward and faithful. All they think about is whether people will like and praise them. Theirs is a threefold sin. First, they are greedy of praise. Secondly, they are very sly and wily in suggesting that the ministry of other pastors is not what it should be. By way of contrast they hope to rise in the estimation of the people. Thirdly, once they have established a reputation for themselves they become so chesty that they stop short of nothing. When they have won the praise of men, pride leads them on to belittle the work of other men and to applaud their own. In this artful manner they hoodwink the people who rather enjoy to see their former pastors taken down a few notches by such upstarts.
"Let a minister be faithful in his office," is the apostolic injunction. "Let him not seek his own glory or look for praise. Let him desire to do good work and to preach the Gospel in all its purity. Whether an ungrateful world appreciates his efforts is to give him no concern because, after all, he is in the ministry not for his own glory but for the glory of Christ."
A faithful minister cares little what people think of him, as long as his conscience approves of him. The approval of his own good conscience is the best praise a minister can have.
But let each one test his own work, and then his reason to boast will be in himself alone and not in his neighbor.—Galatians 6:4