Śatapatha Brāhmaṇa ("of a hundred paths") 5.4.4.19

5.4.4.19

taṃ grāmaṇīḥ sajātāya prayacati | indrasya vajro 'si tena me radhyeti tena grāmaṇīḥ sajātamātmano 'balīyāṃsaṃ kurute tadyadevaṃ samprayacante netpāpavasyasamasadyathāpūrvamasaditi tasmādevaṃ samprayacante

The Grâmanî hands it to a tribesman, with, 'Indra's thunderbolt thou art: therewith serve me!' Thereby the headman makes the tribesman to be weaker than himself. And as to why they mutually hand it on in this way, they do so lest there should be a confusion of classes, and in order that (society) may be in the proper order.