From Sahih Bukhari (Hadith 6176):
Narrated Ibn `Abbas:When the delegation of `Abdul Qais came to the Prophet, he said, "Welcome, O the delegation who have come! Neither you will have disgrace, nor you will regret." They said, "O Allah's Messenger (ﷺ)! We are a group from the tribe of Ar-Rabi`a, and between you and us there is the tribe of Mudar and we cannot come to you except in the sacred months. So please order us to do something good (religious deeds) so that we may enter Paradise by doing that, and also that we may order our people who are behind us (whom we have left behind at home) to follow it." He said, "Four and four:" offer prayers perfectly , pay the Zakat, (obligatory charity), fast the month of Ramadan, and give one-fifth of the war booty (in Allah's cause), and do not drink in (containers called) Ad-Duba,' Al-Hantam, An-Naqir and Al-Muzaffat
Reference: Bukhari 6176