Śatapatha Brāhmaṇa ("of a hundred paths") 5.4.5.3

5.4.5.3

tadyadenametābhirdevatābhiranusamasarpat | tasmātsaṃsṛpo nāmātha yaddaśame 'hanprasuto bhavati tasmāddaśapeyo 'tho yaddaśa daśaikaikaṃ camasamanuprasṛptā bhavanti tasmādveva daśapeyaḥ

And because he there stole after (anu-sam-srip) with those deities, hence the name Samsripah. And because he becomes consecrated on the tenth day, therefore (this ceremony is called) Dasapeya. And because each time ten (men) steal along after each cup, therefore also it is called Dasapeya.