Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 15: The Demigods Appeal to the Lord for Protection
Text 1.15.6

भगवंस्त्वत्प्रसादेन रावणो नाम राक्षसः।
सर्वान्नो बाधते वीर्याच्छासितुं तं न शक्नुमः॥

bhagavaṁs tvat-prasādena rāvaṇo nāma rākṣasaḥ
sarvān
no bādhate vīryāc chāsituṁ taṁ na śaknumaḥ

bhagavan = O Lord; tvat-prasādāt = by pleasing you; rāvaṇaḥ = Rāvaṇa; nāma = by name; rākṣasaḥ = a rākṣasa; sarvān = all; naḥ = of us; bādhate = is harassing; vīryāt = on account of the prowess he has attained; śāsitum = discipline; tam = him; na śaknumaḥ = we can’t.

O Lord, a rākṣasa by name Rāvaṇa is harassing all of us on account of the prowess he has attained by pleasing you. We can’t discipline him.

How did he please Lord Brahmā? And how come these demigods are unable to oppose him? That is explained next.