Musnad Ahmad 30:3334

Yazid ibn Harun narrated to us, Hisham informed us, from Muhammad, from Abu Hurairah, from the Prophet (peace be upon him), who said: "In Friday, there is an hour; no Muslim servant happens upon it while praying, asking Allah for good in it, but He gives it to him." And he gestured with his hand, contracting the fingers of his right hand—three fingers. We said: "He is belittling it, he is belittling it."