According to a narration whenever Imam Zayn al Abideen (RadiAllahu Anhu) rose to take his ablution his face would turn pale and whenever he began to pray his legs would shake. When he was asked the reason he said:
“Are you not aware of Whose presence I am entering? (Abu Nuaym, Hilya, III, 133).
One time when he was praying his house caught fire. However he remained unaware of this. When he finished his prayer and was told of the situation they asked him:
“What was it that made you fail to notice that your house was on fire?”.
Imam Zayn al Abideen (RadiAllahu Anhu) replied:
“The fire that awaits mankind in the hereafter made me forget the fire of this world”.