Muwatta Malik Hadith 228

Yahya related to me from Malik that Yahya ibn Said heard Ata ibn Abi Rabah mentioning that the camel-herders were allowed to throw the stones at night, and saying that this was in the early period (of Islam). Malik said, "The explanation of the hadith where the Messenger of Allah, may Allah bless him and grant him peace, allowed the camel-herders to delay the stoning of the jamras is, in our view, and Allah knows best, that they threw stones on the day of sacrifice, and then threw again two days later, which was the first possible day for leaving, and this throwing was for the day which had passed. They then threw again for the day itself, because it is only possible for someone to make up for something which is obligatory for him, and when something obligatory passes someone by (without him doing it) he must necessarily make it up afterwards (and not beforehand). So (in the case of the camel-herders), if it seemed appropriate for them to leave that day, they would have done all that they were supposed to do, and if they were to stay until the following day, they would throw stones with everybody else on the second and last day for leaving, and then leave."