“Wilayat” means power and authority. In Shia theology, “Wilayat” is the authority invested in the Prophet and the Ahlul Bayt as representatives of Allah
Verily, your Wali is Allah, his messenger, and the believers; those who perform salat, and give zakat while they bow down (in prayer). (Surah Maidah, Verse 55)
“Wilayat,” derived from wila, means power, authority or a right of a certain kind. In Shia theology, Wilayat is the authority invested in the Prophet and the Ahlul Bayt as representatives of Almighty Allah on this earth. According to late Murtaza Mutahhari, Wilayat has four dimensions:
First, The right of love and devotion; this right places the Muslims under the obligation of loving the Ahlul Bayt. Second, The authority in spiritual guidance; this reflects the power and authority of the Ahlul Bayt in guiding their followers in spiritual matters. Third, The authority in socio-political guidance; this dimension of Wilayat reflects the right that the Ahlul Bayt have to lead the Muslims in social and political aspects of life. Fourth, The authority of the universal nature; this dimension reflects universal power over the entire universe that the Prophet and Ahlul Bayt have been vested with by the grace of Almighty Allah.
All Muslims unanimously accept the first dimension of Wilayat of Ahlul Bayt. The second dimension of Wilayat is a commonly held belief of the Shias as well as majority of the Sunnis who belong to Sufi orders. The third and fourth dimensions of Wilayat are unique Shia beliefs, and they are considered as essential parts of the Shia sect.
Whenever the Shias use the term “Imamate” or “Imam”, it encompasses all the four dimensions of Wilayat. It excludes neither the spiritual and universal authority nor the social and political leadership. In this sense, the Shi’i term “Imamate” and “Imam” are more comprehensive than the terms “Khilafat” and “Khalifa”.