The 13th-century Persian poet Saʿdi from Shiraz is considered to be one of the most prominent representatives of medieval Persian ethical literature. His works full of moralizing anecdotes were well known and widely read not only in Persia, but in the other parts of the Islamic world as well. Due to his highly humanistic approach, the relations between people were one of the most important issues discussed by the poet. This article is an attempt to define the status of ‘speech’ in Saʿdi’s moral imagination and to show how it becomes a key instrument in shaping relations with others. In the poet’s opinion, the right words reasonably spoken, just like an appropriate silence, shape the relationship between people and help them avoid conflict and open dispute. Quarrels and confrontations, according to the poet, not only damage a person literally by exposing his flaws and imperfections of character, thereby compromising his reputation (aberu), but may also undermine the basis of social life, generating hostility between people. That is why Saʿdi urges his readers to use soft and gentle speech in dealing with people and always behave in a conciliatory manner in response to aggression and rudeness. Highlighting the moral aspect of speech, Saʿdi shows how kind words form an invisible veil between people, which should be preserved if man desires to maintain his image, good name and dignity.