Skandapurana 5.202.14

5.202.14

yasya no jāyate śuddhiḥ śākhābhirmūlavaṃśagā ..
nigrahastasya kartavyo dvijārho dvijasattamaiḥ .. 14 ..

He whose purification through the branches belonging to the root lineage does not take place / must receive from the best of brahmins the restraint appropriate for a twice-born.”