In Elal al-Sharayeh it is narrated that Imam Sadiq (a.s) said
“God's Prophet made an appointment with someone next to a boulder, and told him he would stay there until he returned. The sun was shining on the Prophet. His companions asked him why he did not move to where there was shade. He replied: “I made an appointment with him here. If he does not come, he will remain in the Heat in the Hereafter.”