Majma al-Zawaid — Hadith 7872

Miqdam bin Shurayh narrates from his father, from his grandfather, who said: I said: "O Messenger of Allah! Tell me of something that will make Paradise obligatory for me." The Prophet (peace and blessings be upon him) said: "Feeding (others) food and spreading the greeting of peace make Paradise obligatory." In one narration the words are: "and good speech."
Tabarani recorded it with two chains, and the narrators of one of them are thiqat (trustworthy). Some hadiths related to this chapter have already passed in the chapter on prayer.