Musnad Abu Ya'la al-Mawsili 117:206

'Abd al-A'la narrated to us, 'Affan narrated to us, Hammad narrated to us, Hisham ibn 'Urwah narrated to us, from his father, from 'Aishah, and Thabit from Anas, from the Prophet (peace be upon him): He heard some sounds and said, "What are these sounds?" They said, "The palm trees, they are pollinating them." He said, "If they did not do it, it would be fine." He said, "So they refrained and did not pollinate them that year, and it became shis (shriveled dates)." This was mentioned to the Prophet (peace be upon him), and he said, "If it is a matter of your worldly affairs, then it is your concern; but if it is a matter of your religion, then it is to me."