Surah As-Saffat 37:126

ٱللَّهَ رَبَّكُمْ وَرَبَّ ءَابَآئِكُمُ ٱلْأَوَّلِينَ

Allāh, your Lord and the Lord of your first forefathers?"

Translation: Saheeh International

Tafsir

God your Lord and the Lord of your forefathers?’ read as predicates allāhu rabbukum and rabbu in the nominative because of the implicit omitted huwa being the subject; or read allāha rabbakum and rabba in the accusative as supplements to ahsana ‘the best of’.

Excerpt from Tafsir al-Jalalayn, commentary on 37:126, via Quran.com. The reader has the full commentary and 9 more tafsirs.