One should be aware that although the imam’s names, especially Imam Ali’s haven’t been mentioned in the Quran, nevertheless, their names can be found in the Prophet’s sayings. One very good example is the hadith of Ghadir which is considered the official announcement of the appointment of Imam Ali as successor to Prophet Muhammad (PBUH) after his decease. This hadith sanadwise (its chain of narrators) is mutawatir (meaning that the number of narrators narrating it is so high that one becomes sure that the hadith is authentic and that all of the narrators can’t be lying or can’t be mistaken in their narration), and concerning its content and meaning, contains clear evidence on Imam Ali (AS) being Imam.
Moreover, the Holy Quran itself has spoken about Imam Ali (AS). The most important verse that has spoken about him, is verse 55 of Surah Ma’idah which says: “Only Allah is your Waliyy (one who is in charge of everything) and His apostle and those who believe, those who establish prayer and pay the poor-rate while bowing down in rokoo’.
”It has been stated in both Shia and Sunni history, tafsir and hadith books that this ayah was revealed when Imam Ali (AS) gave his valuable ring as charity to a needy person while bowing down in Rukoo’. This verse is only talking about Imam Ali (AS) and no one else is meant by this verse. So, although Imam Ali’s name hasn’t been mentioned in the Quran, yet he has clearly been spoken of in it.
There are at least two reasons why Imam Ali’s name hasn’t been mentioned in the Quran. First, because the Quran usually expresses general matters and instructions, and doesn’t get very specific.
For example, Imam Sadiq (AS) was asked why the imams haven’t been named in the Quran. He answered that concerning wilayah (religious authorithy), the Quran has acted the same way that it has regarding salat, zakat, and hajj. The Quran hasn’t been very specific on how to perform these acts, and has only said that they have to be done. The Prophet is the one who has thoroughly explained how these acts must be performed. In the same way, the Prophet has become very detailed in relation to those succeeding him, without any need for them to be explicitly named in the Quran. The second of many reasons for the above-mentioned issue is that since wilayah was a controversial issue, and there were big chances that others would disagree with it, it was much better and safer for the Quran to express it implicitly so that it wouldn’t cause them to go against the Quran and Islam itself! It’s very clear that this isn’t to the benefit of the Muslim Ummah and is a good reason for not mentioning the names of the imams in the Quran. In other words, if the appointment of Imam Ali as successor was to be clearly mentioned in a verse of the Quran, there was a possibility that those who opposed it would somehow falsify or get rid of the verse in order to destroy all of the evidence showing that he is the true successor to the Prophet (PBUH).
As a result, Islam would lose its value as the final religion for mankind in addition to the Quran losing its value as an eternal divine book. Moreover, the Quran says: “Surely we have revealed the Reminder (the Quran), and We will most surely be its guardian.” One of the ways of protecting the Quran is to naturally and very normally block the reasons that might provoke falsification and hostility towards it and not let them even come up in the first place. Consequently, two things take place. Firstly, the Quran doesn’t clearly mention Imam Ali (AS). Secondly, the verses regarding his religious authority such as Ayah Tabligh which is the official announcement of his appointment to being successor, and Ayah Tathir which has to do with the infallibility of the imams, are all located in between verses that don’t have anything to do with these subjects so that the Quran stays protected throughout history, and no one thinks about falsifying it because of the truth it is expressing.