Canto 3 -
Araṇya-kāṇḍa
Chapter 24: Lord Rāma Prepares to Fight With Khara’s Army
Text 3.24.17

स तेनाग्निनिकाशेन कवचेन विभूषितः।
बभूव रामस्तिमिरे विधूमोऽग्निरिवोत्थितः॥

sa tenāgni-nikāśena kavacena vibhūṣitaḥ
babhūva rāmas timire vidhūmo ’gnir ivotthitaḥ

saḥ1 tena = by that; agni-nikāśena = which resembled fire; kavacena = armor; vibhūṣitaḥ = decorated; babhūva = appeared; rāmaḥ = Rāma; timire = in the darkness; vidhūmaḥ = a smokeless; agniḥ = fire; iva = like; utthitaḥ = that had risen.

Decorated by that armor which resembled fire, Rāma appeared like a smokeless fire that had risen in the darkness.

The comparison here is a literary ornament hinting that the rākṣasas would be destroyed in a moment.1

1 Technical note: saḥ rāmaḥ.

1 Rāmāyaṇa-bhūṣaṇa: atropamālaṅkāreṇa kṣaṇena rakṣaḥ-kṣayo dhvanyate.