“Allah has promised to appoint those of you who believe and do good deeds, successors in earth, as He had appointed those before them, and He shall certainly establish their religion which He has chosen for them, and He will give them in exchange security after their fear. They shall worship Me and not associate anyone with Me”
Imam Sadiq (as) explained the above verse as follows, “This verse was revealed about the Qaem (as) and his companions.” (Al Ghaybah by Nomani page 126)
Imam Sadiq (as) was asked about the verse, “Allah has promised to appoint those of you who believe and do good deeds, successors in earth, as He had appointed those before them” (Chapter 24 verse 55).
Imam (as) replied, (This part of the verse) was revealed about Ali bin Abi Talib (as) and the Imams from his sons (as). “And He shall certainly establish their religion which He has chosen for them, and He will give them in exchange security after their fear. They shall worship Me and not associate anyone with Me” (Chapter 24 verse 55) refers to the reappearance of the Qaem (as) (Taweel Al Ayat Al Zahirah page 365)
In reply to a question about the above verse, Imam Sajjad (as) said, I swear to Allah that this (verse) refers to our Shia. Allah will make them (the successors and He will replace their fear with security) through a man from us, the Ahlul Bayt. He is the Mahdi of this nation and he is the one about whom the Messenger of Allah (sawa) said, Even if only one day remains from the life of this world, Allah will extend that day long enough for a man from my family, who bears the same name as mine, to rise. He will fill the earth with justice and equity, just as it will be filled with oppression and inequity. (Tafseer Ayyashi volume 3 page 136)