One-fifth of Booty to the Cause of Allah (Khumus)

Bukhari :: Book 4 :: Volume 53 :: Hadith 385

Narrated 'Amr bin 'Auf Al-Ansari:

(who was an ally of Bam 'Amr bin Lu'ai and one of those who had taken part in (the Ghazwa of) Badr): Allah's Apostle sent Abu 'Ubaida bin Al-Jarreh to Bahrain to collect the Jizya. Allah's Apostle had established peace with the people of Bahrain and appointed Al-'Ala' bin Al-Hadrami as their governor. When Abu 'Ubaida came from Bahrain with the money, the Ansar heard of Abu 'Ubaida's arrival which coincided with the time of the morning prayer with the Prophet. When Allah's Apostle led them in the morning prayer and finished, the Ansar approached him, and he looked at them and smiled on seeing them and said, "I feel that you have heard that Abu. 'Ubaida has brought something?" They said, "Yes, O Allah's Apostle' He said, "Rejoice and hope for what will please you! By Allah, I am not afraid of your poverty but I am afraid that you will lead a life of luxury as past nations did, whereupon you will compete with each other for it, as they competed for it, and it will destroy you as it destroyed them."