Compare LXX Deuteronomy 18:4 and Didache 13:3

"... In the light of these various senses of ἀπαρχή ('first fruits') in the Bible and in Hellenistic Jewish texts, and given the fact that the Jewish offerings to the priests and the poor (tithes) were still being made after 70, the complexities of the Jewish-Christian ἀπαρχή ('first fruits') of Didache 13:3-7 become easier to understand. Besides the prescriptions, which are analogous to or in imitation of the Jewish regulations, Didache 13:3-7 mentions not only the traditional agricultural products (corn, wine and oil) and animals (sheep and cattle), but also money, clothing and possessions of every kind (verse 7). The Didache speaks of all these as being κατὰ τὴν ἐντολήν ('according to the commandment'), although the latter categories are not mentioned in the Torah. It appears, however, that the custom of paying the priestly offering and tithes on all possessions - although never really widespread and common in the first century CE (and even later) - was confined to those who were particularly strict and pious Jews and belonged to religious associations. These associations drew their members above all from among the Pharisees, such as the Pharisee of the parable (Luke 18:9-14a) who boasts: “I give a tenth of what I purchase” (verse 12). It is probably they who originated the post-Torah expansions and elaborations of tithing and of other offerings. The Jewish-Christian ἀπαρχή ('first fruits') of Didache 13:7, destined for the prophets or (in their absence) the poor, seems to reflect these Jewish practices ..."