What is the ruling on one who claims that the Messenger, may God bless him and grant him peace, designated Ali, may God be pleased with him, as his successor, and that the Companions conspired against him?

The statement that the Prophet, peace and blessings be upon him, bequeathed the caliphate to Ali ibn Abi Talib, may Allah be pleased with him, is a false statement with no basis except among the Shi'ites. Evidence indicates that the caliph after him was Abu Bakr al-Siddiq, may Allah be pleased with him. The Companions pledged allegiance to him and unanimously agreed that he was the best of them. It is established through continuous transmission that Ali ibn Abi Talib himself used to say: "The best of this Ummah after its Prophet is Abu Bakr, then Umar." Ali did not claim the caliphate for himself. Rather, the Companions and those who came after them unanimously agreed on the validity of the caliphate of Abu Bakr, Umar, and Uthman. This demonstrates the falsehood of the claim of a bequest to Ali and that the Companions wronged him. Allah has preserved the Ummah from uniting upon error, and it is impossible for it to unite in its most honorable generations upon falsehood, such as the caliphate of Abu Bakr, Umar, and Uthman.