“Your father gave orders before his death, saying, ‘Thus shall you say to Joseph, ‘O please forgive the spiteful deed of your brothers and their sin for they have done you evil.’ So, now, please forgive the spiteful deed of the servants of your father’s Lord.’ “
The Holy One, Blessed is He, said, “You said ‘Ana,’ please forgive us, to Joseph, therefore when the Cohen Gadol enters the Holy of Holies on Yom Kippur to defend his people, he too will say, “Ana.” (Yalkut Shimoni, Vayechi)
The brothers were actually giving us a lesson in asking for forgiveness. (See Grabbing My Attention!) Each time they said, “ana” to Joseph they were admitting another level of guilt.
It is not enough to acknowledge one’s mistakes and sins only once. We must repeat, at least to ourselves, “ana,” please forgive me, so that we absorb the lessons of the experience. (Or Hanefesh Vayechi)