Rule 1: 1. Accusative subject, nominative predicate
After any of the seven particles the subject of the nominal sentence takes the accusative; the predicate, whether a noun, an adjective, a prepositional phrase or a verb, is unaffected. The subject may be a noun (إِنَّ الْمَحْكَمَةَ), a proper name (إِنَّ سَلِيمًا), or a pronoun suffix (إِنَّهُ). Compare فَإِنَّ, the same particle with فَـ prefixed, which is the ordinary continuation after أَمَّا.
إِنَّ الْمَحْكَمَةَ مَفْتُوحَةٌ كُلَّ يَوْمٍ إِلَّا الْجُمُعَةَ.
inna l-maḥkamata maftūḥatun kulla yawmin illa l-jumuʿata
The court is open every day except Friday.
قَالَ الْمُحَامِي إِنَّ الشُّهُودَ ثَلَاثَةٌ.
qāla l-muḥāmī inna sh-shuhūda thalāthatun
The lawyer said that the witnesses were three.
After قَالَ the particle is إِنَّ, with the subject الشُّهُودَ accusative.
أَخْبَرَنِي الشَّاهِدُ بِأَنَّ اللِّصَّ رَجُلٌ طَوِيلٌ.
akhbarani sh-shāhidu bi-anna l-liṣṣa rajulun ṭawīlun
The witness informed me that the thief is a tall man.
لَمْ يَحْضُرِ الْمُتَّهَمُ لِأَنَّ أُمَّهُ مَرِيضَةٌ.
lam yaḥḍuri l-muttahamu li-anna ummahu marīḍatun
The accused did not attend because his mother is ill.
اَلْقَضِيَّةُ قَدِيمَةٌ لٰكِنَّ الْحُكْمَ جَدِيدٌ.
al-qaḍiyyatu qadīmatun lākinna l-ḥukma jadīdun
The case is old but the judgement is new.
لَعَلَّ الْقَاضِيَ يُصْدِرُ قَرَارَهُ غَدًا.
laʿalla l-qāḍiya yuṣdiru qarārahu ghadan
Perhaps the judge will issue his decision tomorrow.
The predicate here is a verbal sentence.