فَانْطَلَقَا ۗحَتّٰىٓ اِذَآ اَتَيَآ اَهْلَ قَرْيَةِ ِۨاسْتَطْعَمَآ اَهْلَهَا فَاَبَوْا اَنْ يُّضَيِّفُوْهُمَا فَوَجَدَا فِيْهَا جِدَارًا يُّرِيْدُ اَنْ يَّنْقَضَّ فَاَقَامَهٗ ۗقَالَ لَوْ شِئْتَ لَتَّخَذْتَ عَلَيْهِ اَجْرًا ( الكهف: ٧٧ )
Fantalaqaa hattaaa izaaa atayaaa ahla qaryatinis tat'amaaa ahlahaa fa abaw any yudaiyifoohumaa fawajadaa feehaa jidaarany yureedu any yanqadda fa aqaamah; qaala law shi'ta lattakhazta 'alaihi ajraa (al-Kahf 18:77)
Sahih International:
So they set out, until when they came to the people of a town, they asked its people for food, but they refused to offer them hospitality. And they found therein a wall about to collapse, so he [i.e., al-Khidhr] restored it. [Moses] said, "If you wished, you could have taken for it a payment." (Al-Kahf [18] : 77)
1 Mufti Taqi Usmani
Then, they moved ahead until they came to the people of a town; they asked its people for food, and they refused to host them. Then, they found there a wall tending to fall down. So he (KhaDir) set it right. He (Mūsā) said, “If you wished, you could have charged a fee for this.”