Musannaf Ibn Abi Shayba 3:5255

Hafs ibn Ghiyath narrated to us, Layth narrated to us, from Isa, from Zayd ibn Arta’ah, from Abu Umamah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "No servant in this world has been given anything better for him than being granted permission to perform two rak'ahs, so he performs them."