The meaning of the restrained

I used to attend at Ibn Abi Layla with regards to inheritance, and he used to push me. When that had (lasted for a) prolonged (time), I complained about him to Ja’far ibn Muhammed, peace be upon them both, so he said: Does he not know that the Messenger of Allah, Allah’s blessings be upon him and his Family, ordered for the return of the restrained and the fulfilment of inheritance? He said: Then I went to him, and he did what he used to do, so I said to him: I complained about you to Ja’far bin Muhammed, peace be upon them both, and he said to me such-and-such. Then Ibn Abi Layla made me swear that he said that, so I swore to him, and he ruled to my favor in that (case).

I was testifying at the presence of Ibn Abi Layla, and he had judged with regards to a man who had made for some of his relatives benefit from a house and not specified a (particular) time for them, and then the man died and his inheritors were present at Ibn Abi Layla, and his relative to whom he made the house was (also) present. Then Ibn Abi Layla said: I see that I (should) leave it like how its owner left it. Then Muhammed bin Muslim al-Thaqafi said to him: Verily, Ali bin Abi Talib, Allah’s blessings be upon him, indeed, judged in this mosque to the contrary of what you have judged. He said: And how do you know? He said: I heard Abu Ja’far, peace be upon him, say: Ali bin Abi Talib, Allah’s blessings be upon him, judged for the return of the restrained and the fulfilment of inheritance. Then Ibn Abi Layla said: Is it with you in a book? He said: Yes. He said: Then send to him and come to me with it. Then Muhammed bin Muslim said: (On the condition that) You must not look into the Book except in that narration. He said: You may do so. He said: Then he showed him the narration of Abu Ja’far, peace be upon him, in the Book and he retracted his judgement. [1]