Musnad Ahmad 30:283

Ibn Idris narrated to us, he said: I heard al-A’mash, from Abu Salih, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "We are the last, the first on the Day of Resurrection, except that they were given the Book before us, and we were given it after them. This is the day which they were commanded to observe, but they differed concerning it, so Allah guided us to it. Thus, the day is for us, and tomorrow is for the Jews, and the day after tomorrow is for the Christians."