"And to Madyan"—meaning: And We sent to Madyan "their brother Shu'ayb." He was their brother by lineage, not their brother in religion. "So he said: O my people, worship Allah and hope for the Last Day"—meaning: believe in it.
﴿وَإِلَى مَدين﴾ أَيْ: وَأَرْسَلْنَا إِلَى مَدْيَنَ ﴿أَخَاهُمْ شعيبا﴾ أَخُوهُمْ فِي النَّسَبِ، وَلَيْسَ بِأَخِيهِمْ فِي الدِّينِ ﴿فَقَالَ يَا قَوْمِ اعْبُدُوا اللَّهَ وَارْجُوا الْيَوْمَ الآخِرَ﴾ أَي: صدقُوا بِهِ