“Indeed, We established him in the land and gave him the means to all things. So he followed a course, until, when he reached the place where the sun sets, he found it setting in a spring of dark mud, and there he found a people. We said, ‘O Dhul-Qarnayn! Either punish them or treat them kindly.’ He said, ‘As for one who commits wrongdoing, we shall punish him; then he will be returned to his Lord, and He will inflict on him a dreadful punishment. But as for one who believes and does righteous deeds, he shall have the best reward, and we shall address him with a gentle command.’”
“Indeed, We established him in the land” means that Allah Most High granted him kingship, enabled him to exercise authority throughout the regions of the earth, and made their peoples submit to him. “And gave him the means to all things. So he followed a course” means that Allah gave him the means that enabled him to attain what he attained, through which he could subdue countries and easily reach the farthest inhabited lands. He made use of the means Allah had given him—that is, he employed them properly. Not everyone who possesses some means makes use of them, nor is everyone capable of doing so. When possession of effective means is combined with putting them to use, the objective is attained; if both or either one is absent, it is not attained.
Allah and His Messenger did not inform us what these means granted to him were, nor have reports transmitted them in a manner that yields certain knowledge. We can therefore do nothing but remain silent about them and pay no attention to what transmitters of Israelite reports and the like relate. We do, however, know in general that they were many powerful means, both internal and external. Through them he acquired a vast army with great manpower, equipment, and organization, and was able to subdue his enemies and easily reach the eastern and western limits of the earth and its various regions. Allah thus granted him the means by which he reached the place where the sun sets. To his eyes, the sun appeared to set in a spring of dark mud—that is, a black spring. This is what anyone ordinarily sees when water lies between him and the western horizon: he sees the sun setting into the water itself, even though it remains at an immense height. There he found—that is, at the place of its setting—a people.
“We said, ‘O Dhul-Qarnayn! Either punish them or treat them kindly.’” ⦗486⦘ That is, either punish them by killing, beating, imprisonment, or the like, or show them kindness. He was given a choice between the two because they were apparently disbelievers or evildoers, or some among them were such. Had they been believers who were not evildoers, he would not have been permitted to punish them. Dhul-Qarnayn possessed such governance in accordance with the Sacred Law that, by Allah’s enabling him to it, he deserved praise and commendation. He therefore said: I shall divide them into two categories. “As for one who commits wrongdoing” through disbelief, “we shall punish him; then he will be returned to his Lord, and He will inflict on him a dreadful punishment.” That is, he will suffer both punishments: punishment in this world and punishment in the Hereafter.
“But as for one who believes and does righteous deeds, he shall have the best reward.” That is, as his reward on the Day of Resurrection, he shall have Paradise and a blessed standing with Allah. “And we shall address him with a gentle command.” That is, we shall treat him kindly, speak gently to him, and deal with him with ease. This shows that Dhul-Qarnayn was one of the righteous kings and friends of Allah—just and knowledgeable—for he acted in accordance with what pleases Allah, dealing with each person as befitted his condition.