Hadith 21 of An-Nawawi's collections discourages selfishness and emphasizes the importance of considering others. The Hadith states, "The merciful will be shown mercy by Ar-Rahman (Allah). Have mercy on those who are on earth, and the One in the heavens will have mercy on you." This Hadith teaches us to be compassionate and kind towards others, and to avoid being selfish and only thinking of our own interests.