الكافي- ط الاسلامية, volume 1, page 28

33. Ali ibn Muhammad has narrated from Ahmad ibn Muhammad ibn Khalid from his father from one of our people that Abu ‘Abdillah (al-Sadiq) (as): “There is nothing (or no difference) between belief and disbelief, but lack of intelligence." So he asked him, “How is that so oh son of Rasulullah (sw)?”. He replied, "Indeed, when a servant raises his desire to a creation, if he had sincerely intended it for Allah, the one he seeks would respond even faster than that."

Translation: Muhammad Sarwar — attributed by Thaqalayn·The Arabic above is the original.

34. A number of our people have narrated from Sahl ibn Ziyad from ‘Ubaydallah al-Dihqan from Ahmad ibn ‘Umar al-Halabi from Yahya ibn ‘Umran from Abu ‘Abdillah (al-Sadiq) (as) that Amir al-Mu'minin (as) used to say: “Through intellect, the essence of wisdom is extracted, and through wisdom, the essence of intellect is extracted. With good governance [of one's actions], righteous manners will be formed." He also used to say, "Contemplation is the life of the discerning heart, just as one walks in darkness with light, through the good purification and minimal hesitation."

Translation: Muhammad Sarwar — attributed by Thaqalayn·The Arabic above is the original.

35. A number of our companions, from Abdillah al-Bazzaaz, from Muhammad bin 'Abd al-Rahman bin Hammaad, from al-Hasan bin 'Ammar that Abu ‘Abdillah (al-Sadiq) (as) in a long narration said, “The first, the beginning, the force and the structure of something is that without which something would be of no benefit. The thing that Allah has made beauty and light for His creatures, the people, is intelligence. With intelligence people come to know their creator and that they are created and that He is the one who has designed them and they are the ones who are being maintained. That it is the creator that is eternal and it is the creatures that are mortals. It is intelligence with which they reason from His creatures, like the heavens, the earth, and the sun the moon, night, the day. In this way they learned that they and the creatures have a creator and maintainer who is eternal. With intelligence they learn about good and bad and that darkness is in ignorance and light is in knowledge. These are facts that they learn with intelligence.” People asked the Imam (a.s), “Can intelligence only be enough for people?” The Imam (a.s) then replied, ‘With guidance from intelligence that Allah has made him to depend on and it is, his beauty and guide, a person of intelligence learns that Allah is his creator and that He is his Lord. Through intelligence one learns that his creator loves and that He dislikes certain things, that the Lord must be obeyed and that certain acts are disobedience to Him and that nothing but intelligence shows him all these facts. One also (with intelligence) learns that only with knowledge and searching one may reach the Creator. That one may not benefit from his intelligence if he can not learn the truth about Him through his knowledge. It then is necessary for a person of intelligence to acquire knowledge and proper moral discipline without which there is nothing else so dependable.”

Translation: Muhammad Sarwar — attributed by Thaqalayn·The Arabic above is the original.