Surah Az-Zalzala

The name. Az-Zalzalah means "The Earthquake," from its opening description of the earth being shaken with its [final] earthquake (99:1), a shaking distinguished from any ordinary tremor by what follows it — the earth discharging what it holds and reporting what has happened on it. It is Medinan, though its subject and short, image-driven style read closer to the short Meccan surahs around it in the mushaf than to the legal and communal material typical of Medinan revelation.

What it is known for. The surah is known for its closing pair of verses stating that whoever does an atom's weight of good will see it, and whoever does an atom's weight of evil will see it (99:7-8) — among the most quoted verses in the Quran on the exactness of recompense, often cited to argue that no deed, however small, is ever treated as too minor to count. It also carries the image of the earth itself testifying to what was done on it, because its Lord has commanded it to (99:4-5), a verse frequently referenced on creation bearing witness against or for a person.

Reading it. At 8 ayahs it is a short surah, read in a couple of minutes. It opens with cosmic upheaval and narrows, within its final two verses, to the smallest possible unit of a deed, so a first-time reader should notice how sharply the surah's scale changes — from an earthquake shaking the whole earth to a single atom's weight of good or evil — within a very short span.