Mahabharata 2.42.9

अश्वमेधे हयं मेध्यमुत्सृष्टं रक्षिभिर्वृतम्पितुर्मे यज्ञविघ्नार्थमहरत्पापनिश्चयः

aśvamedhe hayaṃ medhyamutsṛṣṭaṃ rakṣibhirvṛtampiturme yajñavighnārthamaharatpāpaniścayaḥ

Our plain-language meaning of this verse is waiting for scholar review.