الكافي 1/4/80/23

23. A number of our people has narrated from Sa‘d ibn ‘Abdallah from Ahmad ibn al-Hassan from ‘Umar ibn Yazid from al-Hassan ibn al-Rabi ‘ al-Hamdani who has said that Muhammad ibn Istaq narrated to us from ’Usayd ibn Tha‘laba from ’Umm Hani who has said the following. “Once I met abu Ja’far Muhammad ibn Ali عليه السلام and asked him about he meaning of “I do not (need to) swear by the orbiting (81:15) stars which are visible during the night (81:16) and sit during the day,. “. (81:17) ” The Imam عليه السلام said, “Al-Khunnas, refers to the imam who will disappear in his time when the knowledge about him will be cut off from people in the year two hundred sixty. Then he will reappear like a shooting star in the dark night. If you will attain such time it will light up your eyes with delight.”