Musnad Ahmad 31:218

Yahya narrated to us, from Mujalid, who said: Abu al-Wadak narrated to me, from Abu Sa’id, from the Prophet, peace and blessings of Allah be upon him, who said: "Indeed, the people of the high ranks will see those above them just as you see the brilliant star in the horizon of the sky. And indeed, Abu Bakr and Umar are among them, and they are blessed."