In this passage from the Brahmajāla Sutta the Buddha warns against religious enthusiasm clouding one’s ability to judge whether criticism or praise from others is deserved or not. Rather than reacting with resentment to criticism one should carefully consider whether one deserves the criticism or not and (only) then explain what is true or false.
“If, bhikkhus, others speak in dispraise of me, or in dispraise of the Dhamma, or in dispraise of the Sangha, you should not give way to resentment, displeasure, or animosity against them in your heart. For if you were to become angry or upset in such a situation, you would only be creating an obstacle for yourselves. If you were to become angry or upset when others speak in dispraise of us, would you be able to recognize whether their statements are rightly or wrongly spoken?”
“Certainly not, Lord.”
“If, bhikkhus, others speak in dispraise of me, or in dispraise of the Dhamma, or in dispraise of the Sangha, you should unravel what is false and point it out as false, saying: ‘For such and such a reason this is false, this is untrue, there is no such thing in us, this is not found among us.’
“And if, bhikkhus, others speak in praise of me, or in praise of the Dhamma, or in praise of the Sangha, you should not give way to jubilation, joy, and exultation in your heart. For if you were to become jubilant, joyful, and exultant in such a situation, you would only be creating an obstacle for yourselves. If others speak in praise of me, or in praise of the Dhamma, or in praise of the Sangha, you should acknowledge what is fact as fact, saying: ‘For such and such a reason this is a fact, this is true, there is such a thing in us, this is found among us.’
Dīgha Nikāya 1, Brahmajāla Sutta (The All-embracing Net of Views), I. Paribbājakakathā (Talk on Wanderers )[i]