Musannaf Ibn Abi Shayba 22:305

Ibn Numayr narrated to us, he said: Bashir narrated to us, he said: Malik narrated to us, from Abu al-Safar, from al-Bara’, who said: The last verse that was revealed is: "They ask you for a legal ruling. Say, 'Allah gives you a ruling concerning the one who leaves neither descendants nor ascendants as heirs (al-kalalah).'"