The 125th mitzvah is that we are commanded to separate first-fruits [bikkurim] and to bring them to the Bais Hamikdosh.

The source of this commandment is G‑d's statement,1 "Bring your first fruits to the house of G‑d your L‑rd."

It is clear that this mitzvah applies only when the Bais Hamikdosh is standing; that one brings fruit only from Eretz Yisroel, Syria, and the east side of the Jordan; and only fruit from the seven species.2

The details of this mitzvah are explained in tractate Bikkurim. There it is explained that bikkurim become the kohen's property.