It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that once the Prophet (peace and blessings be upon him) entered the mosque riding on his camel, and Sayyiduna Usama bin Zaid (may Allah be pleased with him) was seated behind him. The Prophet (peace and blessings be upon him) asked for water to drink, and we offered him nabidh. The Prophet (peace and blessings be upon him) drank it and gave the remainder to Sayyiduna Usama (may Allah be pleased with him), and said: "You have done well and acted excellently; continue to do so." That is why we do not wish to change it now.