Imam al-Baqir (a) has said that this verse refers to the family of the Prophet (s). Imam al-Mahdi (ajtf) and his companions will rule over the east and the west of the earth. At that time, the religion of Islam shall prevail over all other religions. All falsities will be removed ; no trace of injustice will be seen. Al-Mahajjah fima Nazala fī-l Qā’īm al-Hujjah by Sayyid Hashim al-Bahrani