The following narration is recorded in Bihār al-Anwār:
The Holy Prophet (S) promised a man that he would wait for him at an appointed place near a stone. The Holy Prophet (S) waited there but the man did not turn up. Morning turned into afternoon while the Holy Prophet (S) stood in the blazing sun. Some of his followers saw him and said, “Please stand in some other place.”
He (S) replied,
“I cannot move away from here till that man returns.”
The man arrived at last. The Holy Prophet (S) said,
“If that man had not come, I would have continued to stand till death!”