The Lord, The Sustainer
رَبُّ السَّمَاوَاتِ وَالْأَرْضِ وَمَا بَيْنَهُمَا فَاعْبُدْهُ وَاصْطَبِرْ لِعِبَادَتِهِ ۚ هَلْ تَعْلَمُ لَهُ سَمِيًّا {65}
The Lord of the skies and the earth and whatever is between the two. Therefore, worship Him and persevere in His worship. Do you know for him a (similar) Name? [19:65]
وَأَشْرَقَتِ الْأَرْضُ بِنُورِ رَبِّهَا وَوُضِعَ الْكِتَابُ وَجِيءَ بِالنَّبِيِّينَ وَالشُّهَدَاءِ وَقُضِيَ بَيْنَهُمْ بِالْحَقِّ وَهُمْ لَا يُظْلَمُونَ {69}
And the earth will shine with the Noor (Light) of its Lord, and the Book would be placed, and they would come with the Prophets and the witnesses, and it would be Judged between them with the Truth, and they would not be wronged [39:69]
علي بن إبراهيم، قال: حدثنا محمد بن أبي عبد الله، قال: حدثنا جعفر بن محمد، قال: حدثني القاسم بن الربيع، قال: حدثنا صباح المدائني، قال: حدثنا المفضل بن عمر، أنه سمع أبا عبد الله (عليه السلام) يقول في قوله تعالى: وَ أَشْرَقَتِ الْأَرْضُ بِنُورِ رَبِّها، قال: «رب الأرض يعني إمام الأرض
Ali Bin Ibrahim said, ‘Muhammad Bin Abu Abdullah narrated to us, from Ja’far Bin Muhammad, from Al-Qasi, Bin Al-Rabi’e, from Sabah Al-Mada’iny,
Al-Mufazzal Bin Umar who heard Abu Abdullah-asws saying regarding the Words of the Exalted: And the earth will shine with the Noor (Light) of its Lord [39:69], The Lord of the earth, means the Imam-asws of the earth’.
قلت: فإذا خرج يكون ماذا؟ قال: «إذن يستغني الناس عن ضوء الشمس و نور القمر و يجتزون بنور الإمام
‘I said, ‘So what would happen when he-asws comes out?’ He-asws said: ‘Then the people would be needless of the illumination of the sun and the light of the moon, and they would be going by the Noor (Light) of the Imam-asws.[1]
NB: https://hubeali.com/isms-and-attributes-of-allah-azwj-part-i-rab-and-its-meanings/
[1] تفسير القمّي 2: 253.