Imam Sadiq (peace be upon him): Aban ibn Taghlib said: I was with Imam Sadiq (peace be upon him) when a man from the people of Yemen entered and greeted him. The Imam (peace be upon him) returned his greeting and said: "Welcome, Sa'd!" The man said: "That is the very name my mother named me with, and few are those who know my name!" The Imam (peace be upon him) said: "You have spoken the truth. O Sa'd al-Mawla!" The man said to him: "May I be your ransom! That was my title." Imam Ja'far Sadiq (peace be upon him) said: "There is no good in titles and epithets. Allah, the Mighty and Majestic, says in the Qur'an: 'And do not call each other by [offensive] nicknames. Wretched is the name of disobedience after [one's] faith.' (Al-Hujurat/11). O Sa'd! What is your occupation?" He said: "May I be your ransom! I am from a family of astronomers, and no one in Yemen is more learned in the science of the stars than we are." Imam Sadiq (peace be upon him) said: "What kind of star is Zuhal (Saturn) among you?" The Yemeni man said: "It is an inauspicious and ominous star." The Imam (peace be upon him) said: "Be silent! Do not utter such a thing; that star is the star of Amir al-Mu'minin (peace be upon him) and the star of the successors and heirs (peace be upon them), and it is the star which Allah, the Mighty and Majestic, mentions in the Qur'an as the shining star." The Yemeni man said: "Then what is meant by 'shining'?" He said: "The place of the rising of this star is in the seventh heaven, and it radiated its light to such an extent that its light became visible in the lowest heaven, and it is from this that Allah, the Mighty and Majestic, named it the shining star (al-najm al-thaqib)."