Musnad Ahmad 1186:3

Abu Ahmad narrated to us, he said: Abdullah—meaning Ibn Abd al-Rahman ibn Ya'la al-Ta'ifi—narrated to us, from Yazid ibn Miqsam, from his patroness Maymunah bint Kurdam, she said: I was riding behind my father, and I heard him asking the Prophet, may Allah bless him and grant him peace. He said: "O Messenger of Allah, I have vowed to slaughter [an animal] at Buwanah." He said: "Is there an idol there, or a Taghut (object of worship other than Allah)?" He said: "No." He said: "Fulfill your vow."