Surah Al-Baqarah 2:248

وَقَالَ لَهُمْ نَبِيُّهُمْ إِنَّ ءَايَةَ مُلْكِهِۦٓ أَن يَأْتِيَكُمُ ٱلتَّابُوتُ فِيهِ سَكِينَةٌ مِّن رَّبِّكُمْ وَبَقِيَّةٌ مِّمَّا تَرَكَ ءَالُ مُوسَىٰ وَءَالُ هَـٰرُونَ تَحْمِلُهُ ٱلْمَلَـٰٓئِكَةُ ۚ إِنَّ فِى ذَٰلِكَ لَـَٔايَةً لَّكُمْ إِن كُنتُم مُّؤْمِنِينَ

And their prophet said to them, "Indeed, a sign of his kingship is that the chest will come to you in which is assurance from your Lord and a remnant of what the family of Moses and the family of Aaron had left, carried by the angels. Indeed in that is a sign for you, if you are believers."

Translation: Saheeh International

Tafsir

And their prophet said to them after they had demanded a sign of his kingship ‘The sign of his kingship is that there will come to you the Ark a chest containing the images of the prophets which God sent down to Adam and which was handed down to them sc. …

Excerpt from Tafsir al-Jalalayn, commentary on 2:248, via Quran.com. The reader has the full commentary and 9 more tafsirs.