Musnad Ahmad 28:226

Anas ibn Iyad narrated to us, Abu Hazim narrated to us, from Amr ibn Shu’ayb, from his father, from his grandfather, who said: I and my brother sat in a gathering that I would not love to have red camels in exchange for. My brother and I approached, and behold, there were elders from the companions of the Messenger of Allah (peace and blessings of Allah be upon him) sitting at one of his doors. We disliked separating them, so we sat to the side. Then they mentioned a verse from the Quran and disputed about it, until their voices rose. The Messenger of Allah (peace and blessings of Allah be upon him) came out angry, his face having turned red, throwing dust at them and saying: "Slowly, O people! By this, the nations before you were destroyed: by their differing over their prophets and their striking some parts of the Books against others. Indeed, the Quran was not sent down for some of it to belie other parts, but rather for some of it to confirm other parts. So, whatever you know of it, act upon it, and whatever you are ignorant of, refer it to the one who knows it."