Abu Dawud Book 16, Hadith Number 3376.

Chapter : Not known.

Narated By Ali ibn AbuTalib : A time is certainly coming to mankind when people will bite each other and a rich man will hold fast, what he has in his possession (i.e. his property), though he was not commanded for that. Allah, Most High, said: “And do not forget liberality between yourselves.” The men who are forced will contract sale while the Prophet (PBUH) forbade forced contract, one which involves some uncertainty, and the sale of fruit before it is ripe.