وَحُصِّلَ مَا فِي الصُّدُورِ
And what is held within hearts is brought out and distinguished. (100:10)
Ḥuṣṣila is also passive. The previous verse describes the uncovering of what lies in graves; this verse turns to concealed inner dispositions and intentions. Mā fī al-ṣudūr is broad, covering what is hidden in the breasts.
The wāw joins two connected disclosures: the removal of outward coverings and the exposure of inward states. This pairing of external and internal disclosure broadens the picture of accountability. Treating the two assertions as unrelated would ignore their clear semantic link.