Surah Al-Isra 17:90

وَقَالُوا۟ لَن نُّؤْمِنَ لَكَ حَتَّىٰ تَفْجُرَ لَنَا مِنَ ٱلْأَرْضِ يَنۢبُوعًا

And they say, "We will not believe you until you break open for us from the ground a spring

Translation: Saheeh International

Tafsir

And they say wa-qālū is a supplement to abā illā ‘insist on’ ‘We will not believe you until you make gush forth for us from the ground a spring from which water issues forth;

Excerpt from Tafsir al-Jalalayn, commentary on 17:90, via Quran.com. The reader has the full commentary and 9 more tafsirs.