He was asked:

“Is there a defining criterion by which the major sins mentioned in the Quran and hadith can be recognized? Is the view that they number seven or seventeen correct? Or the view that they are those on which the revealed laws agree—that is, on their prohibition? Or that they are those that bar the way to knowledge of Allah? Or those that destroy property and lives? Or that they are called major only in comparison and relation to lesser sins? Or that they cannot be identified at all and have been left unspecified, like the Night of Decree? Or, as some report, that their number is closer to ninety? Or that everything Allah has forbidden is a major sin? Or that they are sins carrying a prescribed punishment, or those for which the Fire has been threatened?”

He answered:

All praise is due to Allah, Lord of all worlds.

The soundest view on this question is the one transmitted from Ibn ‘Abbās and cited by Abū ‘Ubayd, Ahmad ibn Hanbal, and others: a minor sin is one that does not incur either of the two penalties—the penalty in this world and the penalty in the Hereafter.

This is the meaning of the statement, “A sin for which there is no prescribed punishment in this world.” It is also the meaning of the statement, “Every sin accompanied by a curse, wrath, or the Fire is a major sin.”

And the meaning of the statement, “For which there is neither a prescribed punishment in this world nor a threat of punishment in