I did a search for "fire" in the NKJV of Isaiah and found 34 verses where the word "fire" can be found.
I also did a search for "torch" but only found this word in Isaiah 51:11 NIV. In the NKJV in this same verse the text contained the word "fire.
Here is the list of verses" -
- Isa 1:7
- Isa 4:5
- Isa 5:24
- Isa 9:5
- Isa 9:18
- Isa 9:19
- Isa 10:16
- Isa 10:17
- Isa 26:11
- Isa 27:11
- Isa 29:6
- Isa 30:14
- Isa 30:27
- Isa 30:30
- Isa 30:33
- Isa 31:9
- Isa 33:11
- Isa 33:12
- Isa 33:14
- Isa 37:19
- Isa 42:25
- Isa 43:2
- Isa 44:16
- Isa 44:19
- Isa 47:14
- Isa 50:11
- Isa 54:16
- Isa 64:2
- Isa 64:2
- Isa 64:11
- Isa 65:5
- Isa 66:15
- Isa 66:16
- Isa 66:24
Isaiah 50:11 may be what you are looking for.
As a side note, the word "mountain" is used as a metaphor for "religion," i.e. the high places where people went to worship their God(s).
I trust that this may help you