Musnad Ahmad 5:87

Muhammad ibn Ubayd narrated to us, Sharhabil ibn Mudrik narrated to us, from Abdullah ibn Naji, from his father, that he traveled with Ali, and he was the keeper of his water container. When he was parallel to Nineveh, while he was on his way to Siffin, Ali called out: "Be patient, Aba Abdullah! Be patient, Aba Abdullah, by the bank of the Euphrates!" I said: "And what is that?" He said: "I entered upon the Prophet, may Allah bless him and grant him peace, one day, and his eyes were overflowing. I said: 'O Prophet of Allah, has someone angered you? What is the matter with your eyes that they are overflowing?' He said: 'Rather, Gabriel just left me a while ago, and he informed me that Al-Husayn will be killed by the bank of the Euphrates.'" He said: "He then said: 'Would you like for me to let you smell some of its soil?' I said: 'Yes.' So he extended his hand, grasped a handful of soil, and gave it to me. I could not control my eyes, so they overflowed."