Musannaf Ibn Abi Shayba 23:118

Abu Usama narrated to us, from Musa ibn Muslim, who said: Ibn Sabit narrated to us, saying: Abdullah ibn Rawahah used to take the hand of a group of his companions and say: "Come, let us believe for an hour. Come, let us remember Allah and increase in faith. Come, let us remember Him through His obedience, perhaps He will remember us with His forgiveness."