John Gill Commentary Deuteronomy 23:25

"When thou comest into thy neighbor`s standing grain, then thou mayest pluck the ears with thy hand; but thou shalt not move a sickle unto thy neighbor`s standing grain." — Deuteronomy 23:25 (ASV)

When you come into the standing corn of your neighbour
Pass through it to go to some other place, the road lying through it, as it often does through standing corn; so Christ and his disciples are said to go through the corn, (Matthew 12:1); but Jarchi says this Scripture speaks of a workman also, and so the Targum of Jonathan, "when you go in to take your hire according to work in your neighbour's standing corn;" but the other sense is best, and is confirmed and illustrated by the instance given, as well as best agrees with what follows.

then you may pluck the ears with your hand ;
the ears of wheat, and rub them, to separate the grain from the husk or beard, and eat it, as did the disciples of Christ; (Luke 6:1); to satisfy hunger: but you shall not move a sickle unto your neighbour's standing corn to cut it down and carry any of it off; which would have been an unjust thing.