For example...
For example, the Prophet, may Allah bless him and his family, concealed his mission till he summoned BanT Hâshim to believe him. Then Allah, the Glorified, ordered him to declare it. The early Muslims kept their faith a secret before the appearance 1 Al- Umran :28. 2 Al- Nahi: 106. 3 Al- Baqara: 195. 4 Al- Nisâ: 94. and spread of Islam. AbIl Tfihib concealed his Islam to protect the Prophet, may Allah bless him and his family, and avoid the accusation of his protection for the Prophet.
But when Islam spread, the unbelievers in Mecca and Medina pretended to be Muslims while the concealed unbelief. The Beginning of Taqiya and its Justifications: The taqiya of the ShVa did not begin at the time of al- Sfldiq, peace be on him. Rather it began at the time of the Commander of the Faithful (AmTr al-Mu’minrn), because he himself used taqiya many times during his days. For instance, he used it when the caliphate was taken from him.
He and some men knew that the caliphate was his own right. But he kept silent because he had no supporters. If he had had forty resolute persons, as he stated, he would have waged war against those people. Men, even those who opposed him, knew his viewpoint towards those people (who took the caliphate from him).
And during the consultation, the people in session decided to pay him homage, provided that he should follow the policy of the two previous caliphs, but he refused that and insisted on following the Book of Allah and the Sunna of His Prophet. The Commander of the Faithful went on using taqiya after he had taken the reins of authority because he knew that some people were ready to oppose him if he told them about everything he had.
The evidence for this was that many of his followers mutinied against him (at the Battles of Al- Jamal and Siffin). So, if he had stated all what he knew and thought, all over the country would have revolted against him.
Though Kufa was dominated by the ShT’a and was the capital of the authority of the Commander of the Faithful, he was not able to change what they had learned from the previous caliphs and was not able to declare what he knew but very little while he was the Owner of the two authorities: the spiritual and the temporal authorities. Just imagine how much more the state was when he had no supporter and the power was against his sons!
The Imams used taqiya as a shield because they knew what that declaration would cause for them and their followers.