Sforno on Exodus 22:30/ספורנו על שמות כ״ב:ל׳

1ואנשי קודש תהיון לי, the manner in which you will prove that you all are men of holy purpose is that you will allow your firstborns to be devoted to the service of Me and you will hand over the tithes, etc., stipulated as “My gifts,” [in matters of specific ritual, seeing that every Jew has to serve Hashem. Ed.] Initially, it was the task of the firstborn to teach the common people the details of Jewish law and ritual. When they do this the result will be והתקדשתם והייתם קדושים, “you will sanctify yourselves and remain holy” (Leviticus 20,7).

2ובשר בשדה טרפה, even the kind of treifah which is neither ritually impure nor confers impurity at all. [if this is forbidden, נבלה, animals which die of other causes than ritual slaughter are certainly forbidden as food. Ed.]