Mukhtasar Muslim (Abridged) 324 — Virtue of Isha and Fajr

Sayyiduna Abdur Rahman bin Abi Amrah reports that Sayyiduna Uthman bin Affan (may Allah be pleased with him) came to the mosque after Maghrib and sat alone. I went and sat with him. He said, "O my nephew! I heard the Messenger of Allah (peace and blessings be upon him) say: Whoever offers the Isha prayer in congregation, it is as if he has spent half the night in prayer (i.e., he will receive such a reward), and whoever offers the Fajr prayer in congregation, it is as if he has spent the entire night in prayer."