Sayyiduna Ibn Mas'ud (may Allah be pleased with him) said, concerning the saying of Allah Almighty: "Whose fuel is people and stones" [Surah al-Baqarah: 24]: "Stones of sulphur, which Allah Almighty keeps with Him however and in whatever way He wills."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8994