Hazrat Musa bin Yasar narrates that Hazrat Salman wrote a letter to Hazrat Abu Darda (may Allah be pleased with him): "Under the shade of the Throne will be a just ruler, and that wealthy person who, when giving charity, keeps his right hand hidden from his left hand, and that man whom a beautiful and noble woman invites towards herself and he says, 'I fear the Lord of the worlds,' and that man who grows up in such a way that his health, his youth, and his death are spent in the love of Allah and in deeds that please Him, and that man whose heart remains attached to the mosques due to his love for them, and that man who remembers Allah and, due to the fear of Allah, his eyes overflow with tears. And there will be two men who meet each other, and one of them says to the other, 'I love you for the sake of Allah.' And it was also written in the letter: Knowledge is like springs; thus, Allah benefits whomever He wills through it. And wisdom that is not spoken is like a body without a soul, and knowledge that is not acted upon is like a treasure from which nothing is spent, and the example of a scholar is like that of a man for whom a lamp is lit on the path; thus, people benefit from its light and everyone prays for him."