"This fire of yours is one part from seventy parts of the fire of Hell, each part of it is like the heat of this one."
Jami` at-Tirmidhi Book 39, Hadith 18
← Previous Hadith "This Fire of yours, which the sons of Adam kindle, is one part from seventy parts of the heat of the Hell." They said: "By Allah! Would it not have been enough O Messenger of Allah?!" He said: "It is sixty-nine parts more – all of them similar in heat.” (Sahih)

Jami` at-Tirmidhi Book 39, Hadith 17 Next Hadith → "The Fire was kindled for one thousand years until it reddened, then it was kindled for one thousand years until it whitened, then it was kindled for one thousand years until it became blackened, so it is dark black."

Jami` at-Tirmidhi Book 39, Hadith 19