After establishing the Orla prohibition, which forbids benefitting from fruits grown during the first three years after a tree’s planting, the Torah (Vayikra 19:24) commands that in the fourth year, the fruits must be treated as “Kodesh Hilulim Le’Hashem” – “sacred, praising G-d.” This means that one must bring the fruits to Jerusalem and partake of them there, giving praise to G-d. These fruits are called “Neta Rebai.” The Sefer Ha’hinuch offers two reasons for this Misva. First, he writes, the fruits that grow in the fourth year are the highest quality fruits, and so the Torah commands bringing them to Jerusalem and expressing praise to Hashem, showing that he devotes his choicest fruit to Hashem. This will bring G-d’s blessing upon all his trees and produce. Secondly, the Sefer Ha’hinuch explains that the Torah presents a number of commands that require people to go to Jerusalem and spend time there – such as the offering of sacrifices, Ma’aser Sheni, Ma’aser Behema, and Neta Rebai. Hashem wants us to spend time in Jerusalem because Jerusalem is the center of Torah learning and spiritual devotion. The requirement to occasionally visit and spend time in Jerusalem will cause people to make arrangements such as purchasing property there, or having their children live there, thus strengthening their connection to the city. This will, in turn, strengthen their devotion to Torah learning, because, as mentioned, Jerusalem is the center of Torah study. The Ramban writes that the fruits grown in a tree’s fourth year are the first of the tree’s fruits that are healthful. In the Ramban’s view, the Torah forbade partaking of a tree’s fruits during its first three years because these fruits are detrimental to one’s health (just as the Ramban explains much of the Torah’s dietary restrictions as aimed at protecting our health). Hence, the fruits grown in the fourth year are, in a sense, the tree’s first fruits. The Torah therefore commanded bringing those fruits to Jerusalem and giving praise to G-d, thanking Him for the first beneficial fruits produced by the tree. If the Neta Rebai fruits are too numerous to bring to Jerusalem, one has the option of “Pidyon” – “redeeming” them by transferring their sanctity onto money. He then brings the money to Jerusalem, and uses the money to purchase food which he eats there in the city. One who redeems his own fruits must add a “Homesh” (one-fifth) to the fruits’ value, whereas one who redeems somebody else’s fruits does not need to add a “Homesh.” This Misva applies to both men and women, but only in the times of the Bet Ha’mikdash. The Rambam maintains that this Misva applies only in the Land of Israel, and has no application at all outside the land. Some Rishonim, however, maintained that when it comes to Kerem Rebai – grapes grown in a vine’s fourth year – the Sages enacted that the grapes are subject to these laws. Accordingly, the Sefer Ha’hinuch writes that if one grew grapes outside Israel during the times of the Bet Ha’mikdash, the grapes that grew during the fourth year would be redeemed, through the transfer of their sanctity onto money. The grapes would then be permissible, and the money would be destroyed such that nobody could use them. One who neglected to follow this procedure in the times of the Bet Ha’mikdash would be in violation of this affirmative command. The Sefer Ha’hinuch adds that those who abided by these laws received great blessing.