“Let another man praise you, and not your own mouth; a stranger, and not your own lips” (Proverbs 27:2).
“A person all wrapped up in himself makes a very small present.” No one is impressed with someone who is impressed with himself.
The praise of a stranger is genuine and high praise indeed. With little, if any, familiarity with you and a lifetime of experience different from yours, a stranger would actually be a much better judge of your skills and uniqueness. For you to be unknown to a another, yet possessing a praiseworthy trait or performing a praiseworthy task would be far more reliable testimony about you.
In light of this, consider the words of a veteran Roman soldier (i.e., a centurion). The crucifixion of Jesus was not his first day on the job, yet when he witnessed the final six hours of this stranger’s life and how He breathed His last, he said, “Truly this Man was the Son of God!” (Mark 15:39).