The Throne Verse (Arabic: آيَة الْكُرْسِي, ʾāyat al-kursī) is the 255th verse of the 2nd surah of the Quran, Al-Baqarah (Q2:255). The verse speaks about how nothing and nobody is regarded to be comparable to Allah.This is one of the best-known verses of the Quran and is widely memorised and displayed in the Muslim world. It is often recited to ward off evil spirits.
There are two opinions among the great Ulama on this matter. Many Ulama say that Ayatul Kursi is just verse 255 alone while other Ulama say that the next two verses are to be recited with it. According to Ayatullah Sistani and many other Ulama, the three verses are to be recited according to obligatory precaution.
1. Reciting Sura Ikhlas (Tawheed) one time gives you the reward of reciting third of the Quran, two times gives you the reward of two thirds of Quran. Reciting it three times gives you the reward of reciting the whole Quran. Imam Muhammad Al-Baqir (AS) said: Sura Qul Howallahu Ahad (Ikhlas) is one third of the Quran. (Wasaa'il Al-Shia, 6:222).
2. Sura Falaq and Sura Naas are great for protection from any harm and evil. There are many Hadeeths in this regard.
3. Ayatul Kursi is one of the greatest verses in Quran according to Hadeeth. Reciting it while going out makes you under the guarantee and protection of Allah till you return back safely. Reciting Ayatul Kursi after Namaz (Prayers) makes you very near to Paradise.
According to Hadeeths narrated from Ahlul Bayt (AS), Kursi of Allah is His Knowledge about Skies and earths and creatures which has got an outer existence, while Arsh is His Full Knowledge about everything, which is more inclusive than Kursi. There are degrees of Knowledge, in which Arsh is deeper, wider and more inclusive than Kursi, that is why we read in the Hadeeth that The Kursi is within The Arsh. In the Hadeeth from Imam Ja'far Al-Sadiq (AS): Everything created by Allah is in the Kursi except His Arsh because it is greater than be included in The Kursi.
Hadeeth of Hanan ibn Sadeer from Imam Al-Sadiq (AS) when he was asked about Arsh and Kursi, he replied: Both of them are great gates of the Unseen. Kursi is the outer gate of the Unseen and Arsh is the inner gate of the Unseen.
Kursi is limited to the skies, earth and what is between them while Arsh is unlimited.
In some narrations we read that The Kursi is the knowledge which Allah granted to His Prophets and messengers, while The Arsh is The Knowledge which no one knows but Allah.
These two verses in Sura Al-Baqara are very clear that no friend can intercede to his friend on the day of Judgment just because of their friendship or partnership (O you who believe, Spend from what have provided you, before a Day comes when there will be no bargaining, nor friendship nor intercession). This is stated in verse 2:254. It is clear that mere friendship or partnership will never allow intercession. In verse 2:255 which is known as Ayatul Kursi, it is stating that no one can intercede but only by Allah's permission. There is no contradiction at all if you understand the real translation of the verses.
Verse 2:254 refutes materialistic intercession, while verse 2:255 states the real intercession by permission of Allah.
Yes it is permissible to recite any Quranic verse including Ayat Al-Kursi on behalf of other believers and for their protection.
After reciting Sura Al Hamd and another Sura, it is allowed during Salaah to recite Ayatul Kursi or any Verse except the verses of obligatory Sajda.
Yes, the two verses are included because many of our leading Scholars relying on authentic Hadeeths say that according to precaution, Ayatul Kursi is three verses ending with Khalidoon.