نَائِب الفَاعِل — Substitute Subject (Passive Voice)
When a verb is in the passive voice (مَبنِي لِلمَجهُول), the actual doer (فَاعِل) is unknown or unmentioned. In its place, the نَائِب الفَاعِل (substitute subject / agent-substitute) takes over the marfūʿ position.
Rule
Every passive verb must have a nāʾib al-fāʿil. It is always:
- Marfūʿ (takes ḍamma or its equivalent)
- In position where the fāʿil would have been
How the Passive Is Formed
| Tense | Pattern | Example |
|---|---|---|
| Past (māḍī) | First vowel → ḍamma; middle vowel → kasra | كَتَبَ → كُتِبَ |
| Present (muḍāriʿ) | First vowel → ḍamma; vowel before last → fatḥa | يَكتُبُ → يُكتَبُ |
What Can Be the Nāʾib al-Fāʿil?
- The direct object (mafʿūl bihi) — most common. When the verb becomes passive, the mafʿūl bihi is promoted to nāʾib al-fāʿil.
- A prepositional phrase (jarr wa majrūr) — when there is no mafʿūl bihi.
- A ẓarf (adverb of time/place).
Nāʾib al-Fāʿil Is Marfūʿ — Always
Even though the nāʾib al-fāʿil was previously manṣūb (as mafʿūl bihi), once the verb becomes passive, it is promoted to marfūʿ. The case changes; the word's position in the sentence becomes the subject position.
Example from Surah An-Noor
يُسَبِّحُ لَهُ فِيهَا — "His praises are glorified therein."
The verb is passive (مَبنِي لِلمَجهُول). There is no explicit fāʿil. The اسْمُهُ (His name) or the understood subject from context functions as the nāʾib al-fāʿil, taking the marfūʿ case.
Session References
- Surah An-Noor Session 2: passive verb in the masājid passage; nāʾib al-fāʿil explained; contrast with the active-voice fāʿil.