The Law Code of Yājñavalkya 3.1.9

3.1.9

iti yamasmaraṇāt || tatas tasmād ūnadvivārṣikād itarapūrṇadvivarṣo yo mṛto 'sau śmaśānaparyantaṃ jñātibhiḥ sapiṇḍaiḥ samānodakaiś ca jyeṣṭhapuraḥsarair anuvrajyo 'nugantavyaḥ | asmād eva vacanād ūnadvivarṣasyānugamanam aniyatam iti gamyate | anugamya ca pareyivāṃsam (RV 10.14.1) ityādiyamasūktaṃ yamadaivatyā gāthāś ca japadbhir laukikenāsaṃskṛtenāgninā dagdhavyo yadi jātāraṇir nāsti | tatsadbhāve tu tanmathitena dagdhavyo na laukikena, tasyāgnisaṃpādyakāryamātrārthatvenotpatteḥ | laukikāgniś ca caṇḍālādivyatirikto grāhyaḥ,

because of this traditional text of Yama. 'Thereafter' means after that child under two years of age; 'the other' who has died having completed two years of age should be accompanied, followed up to the cremation ground by kinsmen, that is, sapiṇḍa and samānodaka relatives, led by the eldest. From this very statement it is understood that accompanying one under two years of age is not fixed. And having accompanied him, while muttering the Yama hymn beginning with "He who has departed" (RV 10.14.1) and chants dedicated to Yama, he is to be cremated with secular, unconsecrated fire if there are no fire-producing sticks. But if they exist, he is to be cremated with fire produced by churning them, not with secular fire, because its production is meant solely for the purpose of the action to be effected by fire. And secular fire should be taken from places other than Caṇḍālas and the like,