Canto 2 -
Ayodhyā-kāṇḍa
Chapter 21: Rāma Consoles Kausalyā and Lakṣmaṇa
Text 2.21.4

नास्यापराधं पश्यामि नापि दोषं तथाविधम्।
येन निर्वास्यते राष्ट्राद्वनवासाय राघवः॥

nāsyāparādhaṁ paśyāmi nāpi doṣaṁ tathā-vidham
yena nirvāsyate rāṣṭrād vana-vāsāya rāghavaḥ

na = not; asya = Him; aparādham = guilty of crime; paśyāmi = I do find; na api = or; doṣam = sin; tathā-vidham = any; yena = because of which; nirvāsyate = has to be exiled; rāṣṭrāt = from the kingdom; vana-vāsāya = to live in a forest; rāghavaḥ = this descendant of Raghu.

I do not find Him guilty of any crime or sin because of which this descendant of Raghu has to be exiled from the kingdom to live in a forest.

Rāma did not commit any crime, that is, He did not betray the king. Nor did He commit any sin categorized as preliminary sins, very great sins, greater sins and topmost sins for which He had to be exiled from the kingdom [according to the Dharma-śāstras].1 

1 In Caitanya-caritāmṛta Madhya-līlā 24.60 purport, Śrīla Prabhupāda refers to pātaka as preliminary sin, urupātaka as very great sin, mahāpātaka as greater sin and atipātaka as topmost sin.