In one of his final addresses to the assembled people of Israel, Moses tells them: “When you enter the land that the Lord your God is giving you as a heritage, and you possess it and settle in it, you shall take of every first fruit of the soil” and bring it to the priest in Jerusalem (Deuteronomy 26:1-2). Moses goes to describe the law of the offering of first fruits and the farmer’s declaration made when he presents the first fruit to the priest. The Midrash (Sifre 297) is less interested in the commandment than in Moses’ language. The Hebrew reads v’hayyah ki tavo, translated as “when you enter.” The Midrash claims that the Hebrew word v’hayyah has but one implication: immediately.
The difficulty with this interpretation is that it assumes that entry into the land of Israel would take place in the Spring, when fruits would be ripening. But at the time of Moses’ address, such an assumption would not be warranted. It would merely be a guess. (Seder Ha-Dorot, the medieval text that fixes dates for key events and personalities in Jewish history, calculates that the Israelites entered the land in the month of Adar and conquered Jericho in Nisan – the beginning of spring.)
This difficulty aside, applied to the context, the Midrash has Moses saying: “When you come to the land, immediately perform the commandment indicated through which you shall be rewarded with possessing the land.” Performing the commandments is essential. But performing the commandments immediately as they are presented earns special commendation. Later, the Sages would rule that a Jew must never set aside a mitzvah that comes to his attention.
Delaying for later an action that can be performed at present says that the action is not really important. Delaying the performance of commandments reveals a kind of cavalier attitude and disrespect for the Lawgiver as well as for the law.