Umar bin Harish says: I asked Sayyiduna Abdullah bin Amr bin al-As (may Allah be pleased with them both) that we are in a place where there is neither dinar nor dirham, so we do transactions of camels and goats on credit for a certain period; what is your opinion about this? Sayyiduna Abdullah (may Allah be pleased with him) said: You have asked a knowledgeable person about this issue. The matter is that the Messenger of Allah (peace and blessings be upon him) prepared an army from the camels of charity, but the preparation was not yet complete when the camels ran out, while the people's need still remained. The Messenger of Allah (peace and blessings be upon him) said to me: Buy camels for us in exchange for the charity she-camels; when they become available, we will pay the owners. Then I bought one camel in exchange for two or three she-camels, until the number was completed. Then, when the charity camels arrived, the Messenger of Allah (peace and blessings be upon him) paid them.