If Jesus had merely said, “Let your light so shine before men, that they may see your good works,”
it would appear that we should seek human praise.
But those who are hypocrites, who cherish honors and covet emptiest glory, seek such praise.
Scripture says about such people, “If I still pleased men, I would not be a bondservant of Christ”
(Gal 1:10).
And, “But let each one examine his own work, and then he will have rejoicing in himself alone, and not in another” (Gal 6:4).
Therefore, our Lord did not merely say, “that they may see your good works,”
but He added, “and glorify your Father in heaven” (Mt 5:16).
The mere fact that people please others by their good works
does not make pleasing others an end in itself.
Instead, please others so that God can be glorified in you.
And those who offer praise [to others for their good works] should honor God, not other people.
Our Lord demonstrated this when He healed the paralytic.
Marveling at His powers, the multitude “glorified God, who had given such power to men” (Mt 9:8).
And Christ’s imitator, the Apostle Paul, says,
“But they were hearing only, ‘He who formerly persecuted us
now preaches the faith which he once tried to destroy.’ And they glorified God in me” 
(Gal 1:23-24).
St. Augustine