مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3346
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated that Ibn 'Abbas (رضي الله عنه) said: When The Messenger of Allah (ﷺ) came (to Madinah), they used to pay one or two years in advance for dates, or two or three years. The Messenger of Allah (ﷺ) said: "Pay in advance for dates for a specified measure and a specified weight, (to be delivered) at a specified time.”
Musnad Ahmad 3370Its isnad is saheeh, al-Bukhari (2253) and Muslim (1604)]