Al-Kahf 18:86

Hatta itha balaghamaghriba ashshamsi wajadaha taghrubu fee AAaynin hami-atinwawajada AAindaha qawman qulna ya thaalqarnayni imma an tuAAaththiba wa-imma antattakhitha feehim husna

Until, when he reached the setting of the sun [i.e., the west], he found it [as if] setting in a body of dark water, and he found near it a people. We [i.e., Allāh] said, "O Dhul-Qarnayn, either you punish [them] or else adopt among them [a way of] goodness."

until when he reached the point of sunset, he found it setting into a miry spring, and found a people near it. We said, “O Dhul-Qarnain, either punish them or adopt good behavior with them.”