Mahabharata 14.61.18

ततः संचोदयामास व्यासो धर्मात्मजं नृपम्अश्वमेधं प्रति तदा ततः सोऽन्तर्हितोऽभवत्

tataḥ saṃcodayāmāsa vyāso dharmātmajaṃ nṛpamaśvamedhaṃ prati tadā tataḥ so'ntarhito'bhavat

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