The Holy Qur'an has proposed ways for people to make up for their mistakes. In the words of Qur'an, this is the act of asking for forgiveness called ‘repentance' which has different types:
1.To deny the mistake one has committed.
2.To admit that you did it, but to try to justify it by bringing excuses.
3.To admit that you have made a mistake or have committed a sin and to promise not to do it again and to try your best to make up for it.
According to Holy Qur'an, the third one is considered the best attitude towards mistakes and sins. That is, learning from mistakes, regretting them, and trying to make up for them.
The Qur'an emphasizes on the fact that we should not postpone making up for our mistakes and should try to correct our wrong deeds as soon as possible.
The Qur'an has talked about this 87 times. For example, "And those who, having done something to be ashamed of, or wronged their own souls, earnestly bring Allah to mind, and ask for forgiveness for their sins,- and who can forgive sins except Allah.- and are never obstinate in persisting knowingly in (the wrong) they have done."
But people who postpone asking for forgiveness are doomed to fail, as Qur'an says, "Of no effect is the repentance of those who continue to do evil, until death faces one of them, and he says, "Now have I repented indeed;" nor of those who die rejecting Faith: for them have We prepared a punishment most grievous."
At the time of death, these people wonder if there is anything they could do; they usually can not.
There actually are exceptions to this. Some people who have lived a lifetime of ignorance, do realize the truth at the end of their lives. There were such people present in Karbala too.
When Imam Hussein told Obeid-allah bin Hur Ja'fi that he had committed sins and that he could repent, Ja'fari answered, "Excuse me. I have a good horse I can give you."
"I neither need you, nor your horse," said Imam Hussein, "I do not rely on the oppressors. Get out of here sooner if you do not want to assist me, because God will send to Hell anyone who hears my cry for help and does not care."
Obeid-allah bin Hur Ja'fi idd not assist Imam Hussein in the most critical moments of his life. He regretted this forever. But there was no use.
Hur ibn Yazid Riya, on the contrary, changed his path after a lifetime of mistakes and joined Imam Hussein and was rewarded with a high position in the Heaven by God.
There are not many people like Hur Riyahi in the history and most people who postpone making up for their evil deeds, usually fail.
Those will be eternally happy who do not postpone good deeds and make up for their mistakes right away, as God says in the Qur'an, "But any that (in this life) had repented, believed and worked righteousness will have hopes to be among those who achieve salvation."
source : www.tebyan.net