Musnad Ahmad 1304:11

'Abd al-Razzaq narrated to us, Ma'mar informed us, from Ibn Khuthaym, from Shahr ibn Hawshab, from Asma' bint Yazid, she said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The Dajjal will remain on the earth for forty years; a year will be like a month, and a month will be like a week, and a week will be like a day, and a day will be like the burning of a palm frond in fire."