Śatapatha Brāhmaṇa ("of a hundred paths") 3.6.1.20

3.6.1.20

athaivamabhipadya vācayati | dhruvāsi dhruvo 'yaṃ yajamāno 'sminnāyatane prajayā bhūyāditi paśubhiriti vaivaṃ yaṃ kāmaṃ kāmayate so 'smai kāmaḥ samṛdhyate

He then makes (the sacrificer) say, while touching it thus (Vâg. S. V, 28), 'Thou art firm: may this sacrificer be firm in this homestead through progeny'--or, 'through cattle!' thus whatever wish he entertains that wish is accomplished unto him.