Exalted is Allah Whom heights of daring cannot approach and fineness of intelligence cannot find. He is such First that there is no extremity for Him so that He be contained within it, nor is there an end for Him where would cease.
Allah kept the Prophets in deposit in the best place of deposit and made them stay in the best place of stay. He moved them in succession from distinguished fore-fathers to chaste wombs. Whenever a predecessor from among them died the follower stood up for the cause of the religion of Allah.
Until this distinction of Allah, the Glorified, reached Muhammad - peace and blessing of Allah be upon him and his descendants. Allah brought him out from the most distinguished sources of origin and the most honourable places of planting, namely from the same (lineal) tree from which He brought forth other Prophets and from which He selected His trustees. Muhammad's descendants are the best descendants, his kinsmen the best of kin and his lineal tree the best of trees. It grew in esteem and rose in distinction. It has tall branches and unapproachable fruits.
He is the leader (Imam) of all who exercise fear (of Allah) and a light for those who seek guidance. He is a lamp whose flame is burning, a meteor whose light is shining and a flint whose spark is bright. His conduct is upright, his behaviour is guiding, his speech is decisive and his decision is just. Allah sent him after an interval from the previous Prophets when people had fallen into errors of action and ignorance. Allah may have mercy on you.
May Allah shower His mercy on you! Do act according to the clear signs, because the way is straight and leads to the house of safety while you are in the place of seeking Allah's favour, and have time and opportunity. The books (of your doings) are open and pens (of angels) are busy (to record your actions) while your bodies are healthy, tongues are free, repentance is accepted and deeds are accorded recognition.
(1) Al-Kulayni, Usul al-Kafi, I, 134;