Hadith 848

'Abdullah bin Salam (May Allah be pleased with him) reported: I heard the Messenger of Allah (PBUH) saying, "O people, exchange greetings of peace (i.e., say: As-Salamu 'Alaikum to one another), feed people, strengthen the ties of kinship, and be in prayer when others are asleep, you will enter Jannah in peace."

[At- Tirmidhi, who classified it as Hasan Sahih].