Fourth...
Fourth: Islam will continue to remain mighty and the devils will be unable to erase it and destroy its effects as long as the twelve Imams (a.s.) exist. Thus, it will always be mighty and lofty and none can destroy it like the previous Divine laws and religions were ruined.
For example, the Shariah of Prophet Moosa (a.s.) and Prophet Eesa (a.s.), in addition to being abrogated by the Shariah of Islam, were distorted in principles and laws through occurrences, wars, Machiavellian politics, manipulations, etc. Hence, whatever is presently available with the Jews and the Christians is not the actual and original Shariah of Prophet Moosa (a.s.) and Prophet Eesa (a.s.), particularly the principles of religion and matters related to beliefs.
As for Islam, then indeed it has remained mighty, lofty and protected from the distortions of the fanatics and the refutation of the deniers. It will continue to be so till the reappearance of the Mahdi (a.t.f.s.) and the Day of Resurrection. For surely, Allah, the High, has placed it in His fortified protection and appointed twelve Imams (a.s.) as guides for it and those who will establish His command in all times till the Day of Judgment.
The above point does not, by any means, contradict the domination of the disbelievers over the Muslims in the past or in the present at some times and in some places, because of their inability to destroy Islam.
The proof of this lies in the fact that Islam is still surviving even after the passage of fourteen long centuries, notwithstanding its enemies who with all their force, number and preparedness, were unanimous in the destruction of Islam and weakening the Muslims with all their material strength, military power and economic muscle. But their conspiracies fail to extinguish the Light of Allah, the High.
Nay, often they dominated the Muslims apparently and ruled over their countries and their wealth but miserably failed to prevent the seeds of this tree from flowering.