Commentary explaining the meaning of the ayahs. One passage often covers several ayahs, so neighbouring ayahs can show the same text.
English Al-Mukhtasar tafsir for Surah Ar-Rahman — Ayah 20
بَيۡنَهُمَا بَرۡزَخٞ لَّا يَبۡغِيَانِ ٢٠
Between them is a barrier that prevents each one of them from transgressing over the other so that the sweet remains sweet and the salty remains salty.