Śatapatha Brāhmaṇa ("of a hundred paths") 2.1.3.8

2.1.3.8

atha yaḥ kāmayeta | bahuḥ prajayā paśubhiḥ syāmiti varṣāsu sa ādadhīta viḍvai varṣā annaṃ viśo bahurhaiva prajayā paśubhirbhavati ya evaṃ vidvānvarṣāsvādhatte

And whosoever may desire to be rich in progeny and cattle, let him set up his fires in the rainy season,--for the rainy season is the common people, and the people means food,--and he certainly becomes rich in progeny and cattle, whosoever, knowing this, sets up his fires in the rainy season.