Sahih Muslim intro-21

Dāwud bin Amr aḍ-Ḍabbī narrated to us, Nāfi’ bin Umar narrated to us, on authority of Ibn Abī Mulaykah, he said:

‘I wrote to Ibn Abbās asking him to write something [pertaining to knowledge] for me and he withheld from me quite a bit, and said: ‘As [if he were] a sincere child, I will write for him something especially suited to his status withholding from him what would not benefit him’. [Ibn Abī Mulaykah] said: ‘So [Ibn Abbās] called for the judgment of Alī [bin Abī Tālib which was a book with which Alī would pass verdicts in Kuffah], and he began to write from it [with respect to the request of Ibn Abī Mulaykah] and he came upon something [not appropriate to the station of Alī regarding the science of verdicts]. So [Ibn Abbās] said: ‘By Allah, Alī did not give judgment according to this unless he was astray’.’