In Sunni Islam, walaya in this context signifies 'friendship' or 'support', whereas Shia Muslims interpret it as 'spiritual authority' because of its exclusivity.
In Shia Islam, this verse thus sanctions the spiritual authority of Ali over all Muslims, after God and Muhammad, and supports his (usurped) right to succeed the prophet.
[7][2] Applied to others, the word wali in the Quran takes various meanings,[7] including 'protecting friend',[8] 'guardian', 'lord', 'master',[7] and (spiritual or material) heir.
[2][9] The two corresponding nouns, walaya and wilaya, are indistinguishable in an unvocalized text,[10] and have nearly identical meanings,[10][11] namely, 'to be near or close to something', 'to be a friend or relative of someone', 'to manage or govern, to have authority or command'.
[8] The strength of these loyalties may vary, however, as suggested by the Shia translation of verse 33:6 of the Quran, "The prophet has a greater claim (awla) on the faithful that they have on themselves.
[14] In particular, the words walaya and wilaya occur twice in the Quran, in verses 8:72 and 18:44, but experts disagree about their correct vocalization.
[18] However, the Sunni translation of the verse is, "Your (real) friends are (no less than) God, His Messenger, and the believers—those who establish prayers and pay zakat and (waw) they bow down humbly (in worship).
Alternatively, the Sunni exegeses Tafsir al-jalalayn and Asbab nuzul al-qur'an consider this verse a response to some companions of Muhammad who complained about their social ostracization by certain Jewish tribes.
[21] For instance, al-Zamakhshari suggests that the verse encourages Muslims to emulate Ali, who did not delay charity until the end of his prayer,[16] al-Razi interprets wali in this verse as a protecting friend,[21] while Ibn Kathir questions the authenticity of the related hadiths about Ali.
By contrast, the particle innama confines the walaya in the verse to God, Muhammad, and those believers who gave alms while praying.
[27] The hadith literature, consensus among scholars, and the occasion of its revelation are further cited in Shia sources to support this interpretation of the verse.
[1] The absolute loyalty ordained in the verse also supports the Shia claim that the prophet and imams are infallible, lest their followers would be misled.
At the same time, there may also be other instances in the Quran where the plural form is used but a single person is meant, including verse 3:168 about Abd Allah ibn Ubayy (d. 631), a tribal chief contemporary to Muhammad.
That is, Shah-Kazemi suggests that the authority in this verse is limited to God, Muhammad, Ali, and all those believers who reach the rank of sainthood.