The Messenger of Allah did not neglect carrying out his mission out of personal fear or for any other personal or family reason.
The reason for concern of the Prophet (PBUH) might be sought elsewhere not in fear from the massacre of his family or himself. He was only worried about the adverse behavior of the hypocrites who had managed to penetrate into the lines of the Muslims, and who had managed to gain a name among people and elite. If the Prophet (PBUH) introduced and banished them, there would be negative reactions by the other companions. On the other hand, the Prophet (PBUH) was worried about the future of Islam because they had openly expressed and manifested their enmity toward Imam Ali (A.S).
In this connection, Shaykh-e Koleyni quotes by solid documents from Zarareh, Fazil ibn Yassar, Bakir bin Amin, Mohammad bin Moslem, Barid bin Muawiyah and Abi al-Jaroud who unanimously quote Imam Muhammad Baqir (A.S) as saying:
"The Almighty God commanded leadership of Islamic Ummah be with Ali (AS) when this verse was revealed "Your ally is none but Allah and [therefore] His Messenger and those who have believed - those who establish prayer and give zakat, and they bow [in worship]."
God commanded obeying those in authority but they did not know what it is and who the one in authority is. So, the Almighty God ordered His Messenger to interpret the Islamic leadership to his people as he does with prayers, zakat, ... When this commandment was given, the Prophet (PBUH) became worried about the fact that the only one deserving leadership of Muslim Ummah may face opposition and enmity because of the unresolved rancor of the battles of Badr, Hunayn, Uhud, or because of wealth and power, or because of their kindred.
source : www.tebyan.net
