John Gill Commentary Deuteronomy 14:23

"And thou shalt eat before Jehovah thy God, in the place which he shall choose, to cause his name to dwell there, the tithe of thy grain, of thy new wine, and of thine oil, and the firstlings of thy herd and of thy flock; that thou mayest learn to fear Jehovah thy God always." — Deuteronomy 14:23 (ASV)

And you shall eat before the Lord your God, in the place which
he shall choose to place his name there
See (Deuteronomy 12:5). There the tithe of all the fruits of the earth was to be eaten; this is the second tithe, as the Targum of Jonathan, and so Jarchi, and which is more particularly described as follows:

the tithe of your corn, of your wine, and of your oil :
see (Deuteronomy 12:7) (See Gill on Deuteronomy 12:7):

and the firstlings of your herds, and of your flocks ;
of which see the note on the above place:

that you may learn to fear the Lord your God always ;
which such a constant practice would inure you to; see (Deuteronomy 10:12) .