"A man came when Allah's Messenger had already prayed, so he said: 'Which of you will give some reward to this person?' So a man stood to pray with him."
Jami` at-Tirmidhi Book 2, Hadith 72
← Previous Hadith "I attended Hajj with the Prophet. I prayed the Subh (Fajr) prayer with him in Masjid AI-Khaif." He said: "When the Prophet finished, he turned (from the Qiblah) and saw two men at the back of the people who had not prayed with him. He said, 'Bring them to me.' So I brought then while they were shuddering with fear. He said: 'What prevented you from praying with us?" They said: 'O Messenger of Allah!' We prayed at our camp.' So he said: 'Do not do that; when you pray in your camp then you come to a Masjid with a congregation, then pray with them. That will be a voluntary prayer for you.'"

Jami` at-Tirmidhi Book 2, Hadith 71 Next Hadith → Allah's Messenger said: "Whoever attends Isha (prayer) in congregation, then he has (the reward as if he had) stood half of the night. And whoever prays Isha and Fajr in congregation, then he has (the reward as if he had) spend the entire night standing (in prayer)."

Jami` at-Tirmidhi Book 2, Hadith 73