Answer:
After the death of Muhammad Abu Bakr unite the Arab tribes.
Step-by-step explanation:
Abu Bakr was one of the fathers-in-law of Prophet Muhammad and among his prominent companions. He was elected the first Khalifa of the Muslims after Muhammad Sahab. In the regime, Abu Bakr followed the principles of poverty and ease propounded by the Prophet.
He had no secretariat and a private treasury. The tax was incurred as soon as the tax was received. He used to take 5,000 dirhams annually himself, but before his death he also returned this money by selling his personal property.