And when they hear ill speech, they turn away from it and say, "For us are our deeds, and for you are your deeds. Peace will be upon you; we seek not the ignorant."
(And there are, certainly, among the People of the Scripture, those who believe in Allah and in that which has been revealed to you, and in that which has been revealed to them, humbling themselves before Allah) (3:199).
سَلَامٌ عَلَيْكُمْ لَا نَبْتَغِي الْجَاهِلِينَ (Peace be on you. We do not seek (the way of) the ignorant. - 28:55). These people have a good quality in that when they hear something stupid from an ignorant foe, they simply say salam, instead of giving a reply. They do not entangle themselves with the ignorant. Imam Jassas (رح) has said that there are two kinds of salarns. One is for salutation, as Muslims do to one another. The other type is for musalamah (adopting peaceful attitude with others) and mutarakah, (to avoid debate) which is to convey to one's adversary that he does not wish to take note of the latter's stupidity. At this place the latter meaning is intended.
Tazkirul Quran
Maulana Wahiduddin KhanOn ayahs 51–55
The real criterion for the acceptance or rejection of the message of Truth is its assessment on the basis of its inherent worth. If the message itself establishes that it is inherently a greater Truth, then that is sufficient to warrant its acceptance. Only Truth can answer Truth. If a man denies a truth and is unable to produce any other superior truth in its place, it indicates that he is denying the Truth as a result of following the dictates of his base desires. Those who behave in this way, have gone astray and are the worst of people. Such people will be treated as transgressors by God.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.