Surah Al-Kahf 18:96

ءَاتُونِى زُبَرَ ٱلْحَدِيدِ ۖ حَتَّىٰٓ إِذَا سَاوَىٰ بَيْنَ ٱلصَّدَفَيْنِ قَالَ ٱنفُخُوا۟ ۖ حَتَّىٰٓ إِذَا جَعَلَهُۥ نَارًا قَالَ ءَاتُونِىٓ أُفْرِغْ عَلَيْهِ قِطْرًا

Bring me bars of iron" - until, when he had leveled [them] between the two mountain walls, he said, "Blow [with bellows]," until when he had made it [like] fire, he said, "Bring me, that I may pour over it molten copper."

Translation: Saheeh International

Tafsir

Bring me ingots of iron!’ namely pieces thereof as large as the blocks of stone to be used in the construction; he used these ingots in his construction placing between them firewood and coal. …

Excerpt from Tafsir al-Jalalayn, commentary on 18:96, via Quran.com. The reader has the full commentary and 9 more tafsirs.