Mishkat al-Masabih #140

Rafi‘ b. Khadij said: God’s Prophet came to Medina when they were fecundating the palm trees. He asked, “What are you doing?” and they replied, “We have been accustomed to do it.” He said, “Perhaps if you did not do it it would be better so they gave it up, but the crop was diminished. They mentioned that to him and he said, “I am only a human being. When I issue any command to you regarding your religion, accept it; but when I issue any command to you based on my own opinion, I am merely a human being.” Muslim transmitted it.