Bismillah AlRahman AlRaheem
A teacher had many good students in his class but had particular regard and high respect for one of them. Some of the students one day asked the teacher the reason for this. In reply he said, I shall tell you tomorrow."
The next day, he handed to each of those students one live chicken. He asked them to take the chickens to a place where they would not be seen by anyone and then slaughter them. After a while, they returned with their chicken duly slaughtered. But his favourite student came back with his chicken alive.
The teacher asked him why he had not slaughtered it. He replied. "You had asked me to go to a place where nobody would see me. I tried hard to find a place where God Almighty could not see me. But I failed. Everywhere went I was sure that God could see me and I could not hide from Him. So I could not carry out your instructions.
On hearing this, the teacher turned to the other students and remarked, "The reason why I respect this student more is because of his constant awareness of the existence of God who can always see him, no matter where he is. Consequently, he does not commit any sin".
The sixth Imam, Ja'far al-Sadiq (a), said to one of his friends, lshaq Bin Ammar, "Fear God as if you are able to see Him because He sees you. And if you think that He is not able to see you, then you become a non-believer. And if you believe that He sees you and you commit a sin in His presence, then you consider Him as the lowest of those seeing you".