Tafsir of Al-Kahf 18:35

{And he entered his garden}: That is, all that constitutes a garden for him, which he enjoys. This is based on the genitive construction (idafa) implying comprehensiveness and generality; thus, it conveys what the dual form conveys, with an addition—which is the indication that he has no garden other than this, and no share in the Garden promised to the righteous. Zamakhshari adopted this view, and it is a subtle meaning that escaped Abu Hayyan, who criticized it and chose the singular form, arguing that one cannot enter two gardens simultaneously, but rather one at a time. This view is devoid of the subtle point indicated above. Likewise, the claim that the singular form is used because one garden is connected to the other is also unfounded. Ibn Abi Hatim narrated from al-Suddi regarding the Almighty’s saying, {We made for one of them two gardens}, that the garden is an orchard; he had one orchard with one surrounding wall, and a river flowed between them, and therefore it was (referred to as) two gardens. He (the Almighty) named it a "garden" (singular) because of the wall surrounding it. This is as you see it; what the context and the dialogue indicate is that the intent is: "And he entered his garden with his companion."

{While he was wronging himself}: This is a circumstantial clause, meaning he was harming himself through his disbelief, as he exposed it to destruction and exposed its blessings to cessation, or (it means) he was placing things in their improper place, as what was fitting for him was gratitude and humility, not what was narrated of him.

{He said, "I do not think that this will ever perish"}: This is an inception (istinaf) based on a question arising from the mention of his entering his garden while wronging himself, as if it were said: "So what did he say at that moment?" Thus, it was said: {I do not think that this will ever perish}—that is, be destroyed or pass away. It is said: bada, yabidu, baydan, bayudan, and baydudatan, meaning it perished.

{Ever}: That is, throughout the duration of life. The intent of "eternity" here is long-lastingness, not its immediate, conventional meaning. It is said it is permissible that he intended the literal meaning because, due to his ignorance and denial of the resurrection, he thought that the kind (genus) would not perish, even if every individual tree within it were to perish, similar to what the philosophers who advocate for the eternity of the world in celestial movements say. This, however, is baseless. It is also said that he intended only that this visible garden, in its individual existence, would not perish, similar to the well-known view of philosophers regarding the celestial spheres themselves. It is as if his love for the world and his vanity regarding it blinded his reason, so he said this; otherwise, it is something no rational person would say, and something no man of virtue would approve of. It is also said that {this} is an allusion to the celestial bodies and terrestrial objects, the heavens, the earth, and the various types of creatures, or an allusion to the world—the outcome being the same. The apparent meaning is what preceded. In any case, perhaps this statement of his was in response to his companion's admonition, reminding him of the perishing of his two gardens, forbidding him from being deluded by them, and commanding him to acquire the enduring good deeds.