Śatapatha Brāhmaṇa ("of a hundred paths") 5.1.3.2

5.1.3.2

sārasvataṃ saptadaśāya stotrāyālabhate | tadetadanatirātre sati rātre rūpaṃ kriyate prajāpatiṃ vā eṣa ujjayati yo vājapeyena yajate saṃvatsaro vai prajāpatistadetena sārasvatena rātrimujjayati tasmādetadanatirātre sati rātre rūpaṃ kriyate

For the seventeenth (or seventeenfold) stotra he seizes one for Sarasvatî: thereby, while there is no over-night performance, it is yet made like the night (performance); for he who offers the Vâgapeya wins Pragâpati, and Pragâpati is the year: by that (victim) for Sarasvatî he now wins the night: hence, while there is no night performance, it is made like the night.