Canto 3 -
Araṇya-kāṇḍa
Chapter 54: Rāvaṇa Brings Sītā to Laṅkā
Text 3.54.19

स तान्दृष्ट्वा महावीर्यो वरदानेन मोहितः।
उवाचैतानिदं वाक्यं प्रशस्य बलवीर्यतः॥

sa tān dṛṣṭvā mahā-vīryo vara-dānena mohitaḥ
uvācaitān idaṁ vākyaṁ praśasya bala-vīryataḥ

saḥ = he; tān = those rākṣasas; dṛṣṭvā = when he saw; mahā-vīryaḥ = [Rāvaṇa] of great prowess; vara-dānena = by the boon he had received from Lord Brahmā; mohitaḥ = [was already] blinded; uvāca = and spoke; etān = them; idam = the following; vākyam = words; praśasya = praised; bala-vīryataḥ = for their strength and heroism;

[Rāvaṇa] of great prowess [was already] blinded by the boon he had received from Lord Brahmā. When he saw those rākṣasas, he praised them for their strength and heroism, and spoke the following words.

NOTE. As we will learn from the Uttara-kāṇḍa (Canto 7 of the Rāmāyaṇa), Rāvaṇa had engaged in severe penances as a result of which he received a boon from Lord Brahmā that he would not be killed by any of the celestial species of life—that is what he wanted and so that is what he was granted.

What kind of penances did he perform? Were they in the mode of goodness or passion or ignorance? The following is the Bhagavad-gītā’s description of penance in the mode of ignorance:

mūḍha-grāheṇātmano yat pīḍayā kriyate tapaḥ
parasyotsādanārthaṁ vā tat tāmasam udāhṛtam

“Penance performed out of foolishness, with self-torture or to destroy or injure others, is said to be in the mode of ignorance.” (Bhagavad-gītā 17.19)

Injuring others was what Rāvaṇa did after he was benedicted by Lord Brahmā and this indicates that he was undoubtedly in the mode of ignorance.