It is mentioned in Nahjul Balagha etc. that Amirul Momineen (a.s.) said: I was with the Prophet when a party of the nobles of Quraish came to him and said to him, “O Muhammad, you have made a big claim which none of your forefathers or those of your family have made. We ask you one thing; if you give us an answer to it and show it to us, we will believe that you are a prophet and a messenger, but if you cannot do it, we will know that you are a sorcerer and a liar.”
The Messenger of Allah said: “What do you ask for?” They said: “Ask this tree to move for us, even with its roots, and stop before you.” The Prophet said, “Verily, Allah has power over everything. If Allah does it for you, will you then believe and stand witness to the truth?” They said “Yes”. Then he said, “I shall show you whatever you want, but I know that you won’t bend towards virtue, and there are among you those who will be thrown into the pit, and those who will form parties (against me).”
Then the Holy Prophet said: “O tree, if you do believe in Allah and the Day of Judgment, and know that I am the Prophet of Allah, come up with your roots and stand before me with the permission of Allah.” By Him who deputed the Prophet with truth, the tree did remove itself with its root and came with a great humming sound and a flapping like the flapping of the wings of birds, till it stopped before the Messenger of Allah while some of its twigs came down onto my shoulders, and I was on the right side of the Holy Prophet.
When the people saw this, they said by way of pride and vanity. “Now you order half of it to come to you and the other half of it to remain (in its place).” The Holy Prophet ordered the tree to do the same. Then half of the tree advanced towards him in an amazing manner and with greater humming. It was about to touch the Prophet of Allah. Then they said, disbelieving and revolting, “Ask this half to get back to its other half and be as it was.”
The Prophet ordered it and it returned. Then I said, “O Prophet of Allah, I am the first to believe in you and to acknowledge that the tree did what it did just now with the command of Allah, the Sublime, in testimony to your Prophethood and to exalt your word. All the people shouted, “Rather a sorcerer, a liar; it is wonderful sorcery, he is very adept in it. Only a man like this (pointing to me) can stand testimony to you in your affairs.”