Shloka 2.78.24
अष्टसप्ततितमः सर्गः — Śatrughna’s Fury and Bharata’s Restraint (Mantharā Episode)
भरतस्य वचश्श्रुत्वा शत्रुघ्नो लक्ष्मणानुजः।न्यवर्तत ततो रोषात्तां मुमोच च मन्थराम्।।।।
hanyām aham imāṁ pāpāṁ kaikeyīṁ duṣṭacāriṇīm |
yadi māṁ dhārmiko rāmo nāsūyen mātṛghātakam ||
I would have slain this sinful Kaikeyī, a woman of wicked conduct—were it not that righteous Rāma would then condemn me as a “slayer of a mother.”
Hearing the words of Bharata, Satrughna, the younger brother of Lakshmana restrained his fury and also released Manthara.
Even when one feels justified, dharma sets inviolable boundaries (e.g., the grave sin of harming a mother-figure); the judgment of the truly righteous (Rāma) becomes an internal moral check.
Śatrughna admits he is held back from killing Kaikeyī only because Rāma would denounce him for matricide.
Rāma’s moral authority: his commitment to dharma is so firm that others restrain themselves to avoid his rightful censure.