Al-Baqarah 2:248

وَقَالَ لَهُمْ نَبِيُّهُمْ إِنَّ ءَايَةَ مُلْكِهِۦٓ أَن يَأْتِيَكُمُ ٱلتَّابُوتُ فِيهِ سَكِينَةٌۭ مِّن رَّبِّكُمْ وَبَقِيَّةٌۭ مِّمَّا تَرَكَ ءَالُ مُوسَىٰ وَءَالُ هَٰرُونَ تَحْمِلُهُ ٱلْمَلَٰٓئِكَةُ ۚ إِنَّ فِى ذَٰلِكَ لَءَايَةًۭ لَّكُمْ إِن كُنتُم مُّؤْمِنِينَ

And (further) their Prophet said to them: "A Sign of his authority is that there shall come to you the Ark of the covenant, with (an assurance) therein of security from your Lord, and the relics left by the family of Moses and the family of Aaron, carried by angels. In this is a symbol for you if ye indeed have faith."