Śatapatha Brāhmaṇa ("of a hundred paths") 4.1.2.4

4.1.2.4

atha yasmātsomam pavitreṇa pāvayati | yatra vai somaḥ svam purohitam bṛhaspatiṃ jijyau tasmai punardadau tena saṃśaśāma tasminpunardaduṣyāsaivātiśiṣṭameno yadīnnūnam brahma jyānāyābhidadhyau

Now as to why he purifies the Soma by means of a strainer (pavitra). When Soma had oppressed his own family-priest Brihaspati, he restored to him (his property); and on his restoring it, he (Brihaspati) became reconciled to him. Still there was guilt remaining, if only for having contemplated oppressing the priesthood.