Tafsir of Al-Qari`ah 101:8

Al-Qāri‘ah (The Calamity): (8) And as for him whose scales are light...

Then the Almighty said: {And as for him whose scales are light} (Al-Qāri‘ah: 8), meaning his good deeds were few, so that the evil deeds outweighed the good deeds.

Abu Bakr (may Allah be pleased with him) said: The scales of those whose scales are heavy were only heavy because they followed the Truth in the world, and the Truth was weighty for them. It is fitting for a scale into which only the Truth is placed to be heavy. The scales of those whose scales are light were only light because they followed falsehood in the world, and falsehood was light for them. It is fitting for a scale into which falsehood is placed to be light.

Muqātil said: This was only the case because the Truth is heavy and falsehood is light.

{Then his refuge will be the Abyss (Hāwiyah)} (Al-Qāri‘ah: 9) {And what will make you know what that is?} (Al-Qāri‘ah: 10).