The first-fruits of the ground were offered unto God just as the
first-born of man and animals.

The law required, (1.) That on the morrow after the Passover
Sabbath a sheaf of new corn should be waved by the priest before
the altar (Lev. 23:5, 6, 10, 12; 2:12).

(2.) That at the feast of Pentecost two loaves of leavened
bread, made from the new flour, were to be waved in like manner
(Lev. 23:15, 17; Num. 28:26).

(3.) The feast of Tabernacles was an acknowledgement that the
fruits of the harvest were from the Lord (Ex. 23:16; 34:22).

(4.) Every individual, besides, was required to consecrate to
God a portion of the first-fruits of the land (Ex. 22:29; 23:19;
34:26; Num. 15:20, 21).

(5.) The law enjoined that no fruit was to be gathered from
newly-planted fruit-trees for the first three years, and that
the first-fruits of the fourth year were to be consecrated to
the Lord (Lev. 19:23-25). Jeremiah (2:3) alludes to the
ordinance of "first-fruits," and hence he must have been
acquainted with the books of Exodus, Leviticus, and Numbers,
where the laws regarding it are recorded.