Musannaf Ibn Abi Shayba 4:665

Yazid ibn Harun narrated to us, from al-Mas'udi, from Hawt al-Khuza'i, who said: I asked Zayd ibn Arqam about the Night of Decree (Laylat al-Qadr), and he did not hesitate nor doubt. He said: It is the night of the nineteenth, the night of the Criterion (al-Furqan), the night the two hosts met.