A number of times before he revealed himself to his brothers, Yosef asked them if their father was alive and they answered in the affirmative. Now when Yosef says "Ani Yosef" he immediately again asks "Ha'Od Avi Chai", is my father still alive. Why does he ask it again and why in the same breath as his great revelation? Furthermore we don't see that the Shevatim answered this question at all. The Bais HaLevi answers that the medrash says that great embarrassment the Shevatim had when Yosef revealed himself will be nothing compared to our embarrassment when we come to Shamayim to our own judgment day. What is the connection?
He explains that Yosef was questioning the consistency of his brothers in their protection of Binyomin. They claimed that they would fight to their death over him because it would kill their father if he were not brought back alive. To this Yosef retorts "I am Yosef", you told my father I am dead and he is still alive so why are you so concerned now?
When we come to Shamayim we will have many excuses to justify our behavior, says the Bais Halevi. However many of the charges we will face will deal with our own internal inconsistencies. You were too tired to help someone who needed a favor? Okay that sounds like a good excuse. But wait! Look here when you were doing something for yourself. Then you had plenty of energy! These are the most embarrassing questions of them all and this is the question that Yosef asked his brothers. For questions like this the Shevatim didn't have an answer and neither will we.