TT #157 · Parashas Shoftim · Third Aliyah · Passuk 18:04
The first of your grain, your wine, and your oil, and the first of the fleece of your flock, you shall give to him.
Torah Temimah points to Chullin 135a.
TT lemma: רֵאשִׁית גֵּז צֹאנְךָ תִּתֵּן לוֹ.
English: ‘The first of the fleece of your flock you shall give to him’ – an obligation upon the owners.
Derash assigning the duty (Bavli) — the verse addresses the owner.
The owner of the flock is the one obligated to give the first fleece to the kohen.