Allah has said:
12|111|In their stories is a lesson for those who possess intelligence. This is not a fabricated tale, but a confirmation of what came before it, and a detailed explanation of all things, and guidance, and mercy for people who believe.
16|89|On the Day when We raise in every community a witness against them, from among them, and bring you as a witness against these. We have revealed to you the Book, as an explanation of all things, and guidance, and mercy and good news for those who submit.
6|114|“Shall I seek a judge other than God, when He is the One who revealed to you the Book, explained in detail?” Those to whom We gave the Book know that it is the truth revealed from your Lord. So do not be of those who doubt.
6|115|The Word of your Lord has been completed, in truth and justice. There is no changing to His words. He is the Hearer, the Knower.
6|116|If you were to obey most of those on earth, they would divert you from God’s path. They follow nothing but assumptions, and they only conjecture.
H 187, Ch. 20, h 10
A number of our people has narrated from Ahmad ibn Muhammad ibn Khalid from ‘Isma’il ibn Mihran from Sayf ibn ‘Umayra from abu al-Maghra from Sama‘a from abu al-Hassan Musa (a.s.) who has said the following. “I asked the Imam, ‘Is everything in the book of Allah and the Sunnah of His messenger or you have a say in it?’ The Imam replied, “As a matter of fact, everything is in the book of Allah and the Sunnah of His messenger (s.a.)’”
H 186, Ch. 20, h 9
A number of our people has narrated from Ahmad ibn Muhammad ibn ‘Isa from Ali ibn Ni‘man from ’Isma‘il ibn Jabir from abu ‘Abdallah (a.s.) who has said the following. “In the book of Allah there is the news of things before you, the reports of the matters after you and the laws to settle your disputes and we know it all.
H 183, Ch. 20, h 6
Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from ibn Faddal from Al- Thaqafi‘laba ibn Maymun from one he narrated from al-Mu‘alla ibn Khunays who has said the following. “Abu ‘Abdallah (a.s.) has said, ‘There is no issue which would be disputed between two people but that there is a principle for it the book of Allah, the Most Majestic, the Most Glorious, only the man’s power of Intelligence is not able to reach it.’”