[His saying: "And let not the witnesses refuse when they are called upon"]
[The first aspect]
2998 - Abu 'Abd Allah Muhammad b. Hammad al-Tehrani narrated to us, Hafs b. 'Umar reported to us, al-Hakam b. Aban reported to us, from 'Ikrimah, from Ibn 'Abbas, regarding His saying: "And let not the witnesses refuse when they are called upon," he said: when they possess testimony.
2999 - Abu Sa'id al-Ashajj narrated to us, 'Uqbah reported to us, from Isra'il, from Jabir, from 'Amir, regarding His saying: "And let not the witnesses refuse when they are called upon," he said: if he has witnessed, then is called, he must not refuse. But if he has not witnessed, then he has the choice; if he wishes he may bear witness, and if he wishes he may not bear witness. A similar [report] was narrated from Mujahid, in one of the narrations, and from Sa'id b. Jubayr, Rabi'ah, and Zayd b. Aslam.
And the second aspect:
3000 - Abu Sa'id b. Yahya al-Qattan narrated to us, Abu Dawud reported to us, from Qays, from Jabir, from Mujahid, regarding the saying of Allah: "And let not the witnesses refuse when they are called upon," he said: It is obligatory.
He said: And I heard al-Sha'bi say: It is a matter of choice as long as he has not witnessed.
3001 - My father narrated to us, Ahmad b. 'Abd al-Rahman reported to us, 'Abd Allah b. Abi Ja'far reported to us, from his father, from al-Rabi', regarding His saying: "And let not the witnesses refuse when they are called upon," he said: A man used to go around among many people, calling them to bear witness, but none of them would follow him, so Allah the Exalted revealed: "And let not the witnesses refuse when they are called upon." A similar [report] was narrated from Qatadah.
And the third aspect:
3002 - My father narrated to us, Abu Salih reported to us, Mu'awiyah b. Salih narrated to us, from 'Ali b. Abi Talhah, from Ibn 'Abbas, His saying: "And let not the witnesses refuse when they are called upon," meaning: whoever among the Muslims is needed, and he has borne witness to a testimony, or he possesses a testimony, it is not permissible for him to refuse when he is called upon.
A similar [report] was narrated from al-Hasan, saying: It combines two matters.
[His saying: "And do not be weary"]
3003 - Abu Zur'ah narrated to us, Yahya b. 'Abd Allah b. Bukayr reported to us, Ibn Lahi'ah narrated to me,