Recognition and perception

إِذْ دَخَلُوا۟ عَلَيْهِ فَقَالُوا۟ سَلَـٰمًا ۖ قَالَ سَلَـٰمٌ قَوْمٌ مُّنكَرُونَ

When they entered upon him and said, "[We greet you with] peace." He answered, "[And upon you] peace; [you are] a people unknown."