In addition to preparing the festival meals, there are other important preparations that are carried out before the onset of the festival, including ones that are unique to Shavuot.

On the eve of the festival, many people decorate their homes and synagogues with green vegetation. The reason for this custom is twofold: First, the Midrash derives from the verse: “The flocks and the cattle shall not graze before that mountain” (Exodus 34:3), that Mount Sinai was covered with greenery in anticipation of the giving of the Torah there. Another reason, based on a mishna (Rosh HaShana 1:2), is that on Shavuot we are judged concerning the fruits that will grow on our trees during the upcoming year, and the decorative vegetation reminds us to request from God that the trees should yield a substantial and quality harvest.

There are other things that one should do on the eve of Shavuot:

One should leave a twenty-four-hour candle burning before the holiday, so that it will be possible to transfer fire from it for cooking and other uses during the holiday.

When the holiday occurs on a Friday, one must make an eiruv tavshilin before the start of Shavuot, so that it will be permitted to cook food on the holiday for the adjacent Shabbat, and also to light the Shabbat candles toward the end of the holiday.

Further reading: For the laws of eiruv tavshilin, see p. 474.

If Shavuot is on a Sunday, one must be careful to light the festival candles only after Shabbat has ended. This time is generally listed in synagogue calendars. The candles must be lit from an existing flame that was lit before Shabbat. Before lighting the candles, one should recite the formula: “Blessed be He who separates between the sacred and the sacred,” that is, between the more intense holiness of Shabbat and the lesser holiness of the holiday. Under no circumstances may one light the candles any earlier, as this would be a desecration of Shabbat.

When Shavuot falls on a weekday, some are accustomed to light the candles at the start of the festival, before sundown, while others light them after the holiday has already begun, just before the beginning of the meal. Those who light after the festival has started should use only an existing flame; that is, they should light a match from a fire that was burning before the festival began. One may not produce a new fire on the holiday itself.

When lighting the candles, one recites two blessings:

“Blessed are You, Lord our God, King of the universe, who sanctified us through His commandments, and commanded us to light a candle for the festival.”

“Blessed are You, Lord our God, King of the universe, who has given us life, sustained us, and brought us to this time.

Further reading: For more details regarding the halakhot of candle lighting, see p. 381. For more on the festival of Shavuot, see A Concise Guide to the Sages, p. 309; A Concise Guide to Mahshava, p. 99.