Shaykh Tabarsi has narrated from Ameerul Momineen (a.s.)
that he said:
One day in holy Mecca the Messenger of Allah (s.a.w.a.) summoned a tree towards himself. That tree arrived while each of its branches was intoning divine praise and glorification.
The Holy Prophet (s.a.w.a.) said: “Split into two.” They saw it split into
two. After that he (s.a.w.a.) said to the two parts: “Join together.”
People saw those two parts joining each other.
Then he (s.a.w.a.) said: “O tree, testify for my prophethood and messengership.” It testified. Then he (s.a.w.a.) said: “Go back to your place reciting divine praise and glorification.”
Behaarul Anwaar, vol. 10, p. 48
Isbaatul Wilayah (Part One) – Ayatullah AliNamazi Shahroodi (r.a.)