Ten years ago, or less than that, I was not consistent in my prayer, as I would pray one day and leave off the next, out of negligence on my part, and I do not know the number

The questioner : Ten years ago, or less than that, I was not consistent in my prayer, as I would pray one day and leave off the next, out of negligence on my part, and I do not know the number of times I did not pray or the number of days I did not pray. What is the ruling in this case, O honorable Shaykh?

The Shaykh : It appears from his question that the man has become upright and is now praying. This is sufficient, and he does not need to repeat his past prayers. Rather, he should rectify his deeds and increase in voluntary prayers, for good deeds erase bad deeds.
I said that because this is the stronger opinion among the scholars' views. Some scholars say: if one leaves off prayer for a period, it is obligatory for him to make it up, even if he did so intentionally. But the stronger opinion is that making it up is not prescribed, and that if he were to make it up, it would not benefit him, due to the saying of the Prophet (peace and blessings be upon him): .
And this person who left off prayer, if he left it off in a way that constitutes disbelief, then the disbeliever does not make up prayers, as is well known, due to the saying of Allah the Exalted: . And if he left it off in a way that does not constitute disbelief, such as if he was praying and then leaving it off, then every time-bound act of worship, if a person takes it out of its time without a valid legal excuse, he does not make it up, because if he were to make it up, it would not be accepted from him. We ask Allah to keep our brother the questioner firm, and to make the blessing of religion and Islam permanent for us and for him.