A sincere compliment that is deserved, has a great moral value. It helps and encourages one to be told that his efforts are approved and appreciated.
Columnist John R. Gunn writes that, "The apostle Paul frequently used this means to encourage and stimulate the people to whom he ministered. On one occasion he had sent Timothy to visit the Christians in Thessalonica to see how they were getting along in the Christian life. Timothy reported that in spite of persecution and many afflictions, they were standing true to their belief and faithful to duty."
Here are a few lines from the letter Paul wrote to the Thessalonian Christians after receiving Timothy's report, Timothy brought us good tidings of your faith and charity. We are comforted over you; we give thanks for you, remembering your work of faith and labor of love and patience of hope.
Paul was not a man to flatter people, his words were sincere expressions of genuine appreciation. They had done well and Paul commended them, not in a way to puff them up, but in such a manner as to encourage them to go on in their well doing.
Here is a worthy example for you and for me. We should never flatter anybody; only vain people like flattery and it only serves to swell that vanity, but often we can help and encourage people by a simple word of commendation.
A sincere compliment is one of the best stimulants to worthy living and noble effort. Try it out on the peole around you and see how it works