Shloka 5.22.20
रावणस्य तर्जनं सीताया धर्मोक्तिः (Ravana’s Threats and Sita’s Dharma-Centered Reply)
असन्देशात्तु रामस्य तपसश्चानुपालनात्।न त्वां कुर्मि दशग्रीव भस्म भर्मार्ह तेजसा।।।।
asandeśāt tu rāmasya tapasaś cānupālanāt | na tvāṁ kurmi daśagrīva bhasma bhasmārha tejasā ||
But since I have not received Rāma’s command—and because I preserve the discipline of my austerity—I do not reduce you to ashes with my fiery power, O Ten-necked one, though you deserve to be burnt.
"O Ravana! I can reduce you to ashes through the fire of my chastity. But I do not have Rama's permission and I want to preserve my power of ascetism even though you are fit to be consigned to the flames.
Power must be governed by dharma: even when capable, Sītā restrains herself, acting only within rightful bounds (Rāma’s mandate) and preserving her disciplined virtue.
Sītā confronts Rāvaṇa in captivity, declaring that her inner spiritual power could destroy him, yet she will not act outside dharmic restraint.
Maryādā (ethical boundary-keeping) and tapas-based self-control—strength expressed through restraint, not retaliation.