Riyad us Saliheen: Hadith 849

I heard the Messenger of Allah (ﷺ) 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].