Ramayana
अश्वमेधो महायज्ञः पावनः सर्वपाप्मनाम् । पावनस्तव दुर्धर्षो रोचतां रघुनन्दन ॥ 7-84-2 ॥
"The Ashvamedha is a great sacrifice that purifies one of all sins; this purifying and unassailable rite, O delight of Raghu's line, may it find favor with you."
english translation