He will say: "Alas! Would that I had sent forth for my life!"
meaning, if he was a disobedient person, he will be sorry for the acts of disobedience he committed. If he was an obedient person, he will wish that he performed more acts of obedience.
This is similar to what Imam Ahmad bin Hanbal recorded from Muhammad bin Abi `Amirah, who was one of the Companions of the Messenger of Allah . He said,
"If a servant fell down on his face (in prostration) from the day that he was born until the day he died as an old man, in obedience to Allah, he would scorn this act on the Day of Judgement. He would wish to be returned to this life so that he could earn more reward and compensation."
Allah then says,
فَيَوْمَيِذٍ لاَّ يُعَذِّبُ عَذَابَهُ أَحَدٌ