Imam ‘Ali (a.s.) said:
الثَناءُ بِأَكْثَرَ مِنَ الاسْتِحْقاقِ مَلَقٌ و التَّقْصِيرُ مِنَ الأسْتِحْقاقِ عَىٌّ أَوْ حَسَدٌ
When praise and commendation is more than merited and deserved it is flattery and when less than merited it is either debility in expression or envy. 1
Undoubtedly, the worthy individuals and their good attributes and deeds should be praised and appreciated, and in this way we shall encourage and support them to carry on with their good work.
But praise should be proportionate to the merit . Otherwise, it would have negative and harmful consequences. If it is more than merit, it becomes flattery which hurts the dignity of the speaker and also causes self-conceit and self-admiration in the one who is flattered. And if it is less than merit, it discourages the good doers and shows that the speaker is either envious or weak in his power of expression.