Musannaf Ibn Abi Shayba 22:162

Waki' narrated to us, Al-A'mash narrated to us, from Abu Salih, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Would any of you like, when he returns to his family, to find among them three pregnant she-camels, fat and large?" He said: We said, "Yes." He said: "Then three verses that one of you recites in his prayer are better for him than three pregnant she-camels, fat and large."