The Prophet (sallallähu alaihi wasallam) passed by a woman who was weeping beside a grave.
He told her to fear Allah and be patient.

She said to him, “Go away, for you have not been afflicted with a calamity like mine.”
And she did not recognize him.
Then she was informed that he was the Prophet (sallallähu alaihi wasallam).
So she went to the house of the Prophet (sallallähu alaihi wasallam) and there she did not find any guard.
Then she said to him, “I did not recognize you.”

He said, “Verily, the patience is at the first stroke of a calamity.”

[Bukhari Book:23 No:372]