Hiranyakeshigrihyasutra 1.1.3.9

1.1.3.9

cittaṃ ca svāhā \ cittiśca svāhā \ iti jayāñjuhoti \ cittāya svāhā \ cittaye svāhā \ iti vā \9\

The Gaya (oblations) he sacrifices with (the thirteen Mantras), 'Thought, svâhâ! Thinking, svâhâ!'—or, 'To thought svâhâ! To thinking svâhâ!' (&c.);