A conditional with a consequence attached
Both halves of the sentence are stated.
وَإِذْ تَأَذَّنَ رَبُّكُمْ لَئِن شَكَرْتُمْ لَأَزِيدَنَّكُمْ ۖ وَلَئِن كَفَرْتُمْ إِنَّ عَذَابِى لَشَدِيدٌ
…la-in shakartum la-azīdannakum, wa la-in kafartum inna ʿadhābī la-shadīd.
And [remember] when your Lord proclaimed, 'If you are grateful, I will surely increase you [in favor]; but if you deny, indeed, My punishment is severe.'"
Source
The Qur'an · 14:7
Qur'an
- Qur'anic text in the Uthmani script via Quran.com; translation: Saheeh International