Grammar term · Nahw · syntax
وَاو / لَام الْقَسَم
waw / lam al-qasam
Oath particle (waw/lam of qasam)
Nahw · syntaxSpecific particleadvanced term486+ in the Qur'an
In one line
The oath pair: وَ swears by something (وَاللَّهِ), and لَ opens the sworn answer (لَأَفْعَلَنَّ).
The modern list
حُرُوفُ الْقَسَمِ وَهِيَ: (الْوَاوُ، وَالْبَاءُ، وَالتَّاءُ)، هَذِهِ الْحُرُوفُ الثَّلَاثَةُ حُرُوفُ جَرٍّ وَقَسَمٍ. (التَّاءُ) لَا تَدْخُلُ إِلَّا عَلَى لَفْظِ الْجَلَالَةِ (اللهُ)، وَ(الْوَاوُ) وَ(الْبَاءُ) تَدْخُلَانِ عَلَى كُلِّ مُقْسَمٍ بِهِ.
“The particles of oath are the waw, the ba' and the ta' — all three are particles of jarr and oath. The ta' enters only upon the name of Allah, while the waw and the ba' enter upon anything sworn by.”
(النحو التطبيقي)
Key words in the Arabic
مُقْسَمٍ بِهِthe thing sworn by
حُرُوفُ جَرٍّ وَقَسَمٍjarr + oath particles
Understand it
Swearing takes two particles working in relay. The waw opens the oath and puts the sworn-by noun into jarr — وَالْعَصْرِ — with the ba and ta as the pin's alternatives, the ta reserved for Allah's name alone. The lam of qasam then opens the oath's answer — لَأَجْتَهِدَنَّ — usually locking arms with nun al-tawkid, or with إِنَّ when the answer is nominal. With the waw and ta the oath verb أُقْسِمُ must stay hidden; only the ba may show it.
How to spot it
Recognition test
Speech-opening وَ + noun in jarr = the oath waw (the 'atf waw never opens discourse). A following لَ + mudari' + نَّ, or لَ inside an إِنَّ-sentence, is the answer of that oath.
In the Qur'an
وَٱلْعَصْرِ إِنَّ ٱلْإِنسَٰنَ لَفِى خُسْرٍ
Al-Asr 103:1–2 — “By time — indeed mankind is in loss”
وَ swears by ٱلْعَصْر (jarr); the لَ in لَفِى opens the oath's answer inside the إِنَّ-sentence.
Related terms