Sayyiduna Abdullah bin Salam (may Allah be pleased with him) says: When the Prophet (peace and blessings be upon him) came to Madinah and it was said that the Messenger of Allah (peace and blessings be upon him) had arrived, I too came along with the people to see him (peace and blessings be upon him). When I saw his (peace and blessings be upon him) face, I recognised that this could not be the face of a liar. The first thing I heard from the Prophet (peace and blessings be upon him) was this: "O people! Feed others, spread the greeting of peace, maintain the ties of kinship, and pray at night when people are asleep, and you will enter Paradise in peace."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4647