Verses with the word furnace in the New Testament (4 verses):

Matthew 13:42
And shall cast them into a furnace of fire: there shall be wailing and gnashing of teeth.

Matthew 13:50
And shall cast them into the furnace of fire: there shall be wailing and gnashing of teeth.

Revelation 1:15
And his feet like unto fine brass, as if they burned in a furnace; and his voice as the sound of many waters.

Revelation 9:2
And he opened the bottomless pit; and there arose a smoke out of the pit, as the smoke of a great furnace; and the sun and the air were darkened by reason of the smoke of the pit.