Deuteronomy 26:14 "Nor given (of) it for the dead."

Ma'aser Sheini must be brought up to Jerusalem and eaten there.

A person may find it difficult to carry all his Ma'aser Sheyni to Jerusalem over a long distance.

In this case, the Torah allows that person to redeem his Ma'aser Sheini and use the acquired money in Jerusalem.

The Torah also allows him to use this money in Jerusalem at time that is convenient for him, (but no later than three years after he has redeemed his produce).

Upon reaching Jerusalem, he may buy food or drink with the money and then he must eat the food in Jerusalem.

This Negative Mitzvah cautions us not to spend this money on anything else but food and drink.