Musannaf Ibn Abi Shayba 33:1405

Yahya ibn Yaman narrated to us, from Ash'ath, from Ja'far, from Sa'id ibn Jubayr, regarding the saying of Allah: "Is one who is devoutly obedient during periods of the night, prostrating and standing [in prayer], fearing the Hereafter..." He said: He fears the punishment of the Hereafter.