After the incident of Ghadir, a person named Malik Ibn Harith came to the Prophet (PBUH) and said: You ordered us to testify to the oneness of God and that you are His Messenger, but you were not satisfied with this then you appointed this young man (Hazrat Ali (as) ) as your successor. Is this from God or you? The Prophet (saw) said: I swear to God that there is no Deity but Him, this is from God Almighty.
source : erfan.ir
