Skanda Purana 5.256.4

5.256.4

kramo'yaṃ sarvavarṇānāṃ prakṛtīnāṃ sadaiva hi ..
krameṇa rahito yastu karoti manujo japam ..
tasya prakupyati vibhurnarakādipradāyakaḥ .. 4 ..

This order is indeed prescribed for all castes and common people at all times. / But the mortal who recites the mantra disregarding the proper order— / against him the all-pervading Lord grows wrathful, consigning him to hell and the like. (4)