Fire did not Burn - Knife did not Cut

The fire ignited by the order of Namrood to burn Ibrahim (a.s.) was made bereft of its burning property, by Allah. It is said, that the fire was so intense that birds flying at a height of three miles used to be scorched by the heat and drop dead.

So they threw Hadhrat Ibrahim (a.s.) into the fire with the help of a catapult from far away. In the Holy Qur'an Allah says: "We said: O fire! be coolness and peace to Ibrahim."
(Surah Anbiya:69)

The fire immediately lost its essential property of burning, and cooled down; and if Allah had not ordered it to be peaceful (safe) for Ibrahim (a.s.) it would have become colder and may have frozen Ibrahim (a.s.) to death.

In the same way when Ibrahim (a.s.) proceeded to slaughter his son Ismail (a.s.) the knife was blunted by Allah's command. Ibrahim (a.s.) threw the knife away and a voice emerged from it. "The Khalil (friend) of Allah commands me to cut and the Lord of the Khalil restrains me from it."

(extract from the book "Greater Sins" by Shaheed DastGhaib)