Christians came to debate King Harun Ar Rashid. King Harun Ar Rashid asked Al Shafi, who was a boy at that time to debate them. Al Shafi threw his prayer rug on the river, and standing on it told the Christians: "come here and we'll debate".
Muhammad (peace be upon him and his family) once prayed for rain; no sooner did he put down his hands that clouds gathered and it was raining for a week (see Bukhari).
Umar once sent a letter to the Nile, and when the Nile received it, it started to flow again.
Ibrahim Adham once woke up, in his palace, which roof was transparent, to find a man over his roof walking. The man asked Ibrahim Adham if he saw his camel. Ibrahim Adham was surprised asking him how could he be looking for his camel on a roof. Then the man told him, more or less:
"there is more chance for me to find my camel on this roof than for you to find God in the midst of this luxurious lifestyle".
Then Ibrahim Adham gave up his kingdom, went away from it and repented.
Muhammad (peace be upon him and his family) said the Muslims will split into 73 factions, and only one will be saved.
This is enough admonition.