Because that is the system explicitly set forth in the Torah (Genesis 1:5, Leviticus 23:32).
In Genesis 1:5 it says "And there was evening, and there was morning-the first day". Since the "evening" comes before the "morning" in the sentence, Jews extrapolate that the evening precedes the morning in the same day.
In Judaism, all days start at sunset. The reason for this is found in the biblical account of creation: "And it was evening and it was morning of the first day"... and so on for all the days of creation. Evening came first, before the day. So Jewish holidays, like all other days, begin at sunset.
We light the menorah because it is Chanukkah and on Chanukkah we need to publicize the miracle of the Maccabees and the oil of the Temple burning for 8 days. The best time to light candles is at sundown or in the evening, so that people can easily see them.
Dead Jews have to be buried before sunset on Friday, because the Jewish Sabbath is from Friday night (at sundown) to Saturday night (at sundown) and no work (such as burying a dead body) can be done on the Sabbath.
I think it's just a matter of convenience, not a requirement.
Shabbat begins on Friday at sunset.
All Jewish days begin at nightfall. This follows from Genesis 1:5 "And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day." Later days in the creation story in Genesis are described similarly, that is, "the evening and the morning" are described as making up each day.
The Jewish day of rest is called the Sabbath, and it begins on Friday evening at sundown and lasts until Saturday evening at sundown. It is observed as a time of rest and worship.
Sundown.
Friday at sundown until Saturday at sundown.
The Jewish Sabbath was Saturday, however the Sabbath began Friday with sundown and ended Saturday with sundown. Sunday became the Christian day of worship because Sunday is the day Christ rose from the dead. Catholics have retained the Jewish custom of the Sabbath beginning the day before sundown. Thus for Catholics "Sunday" (the Sabbath) technically begins on Saturday evening with sundown, and ends Sunday with sundown.
Shabbat which starts Friday at sundown and ends Saturday after twilight.
Shabbat starts at sundown Friday night and ends sundown Saturday night, the 7th day of the week.
Jews do not call the sabbat "Saturday", it is called 'Shabbat'. Shabbat happens to start Friday at sundown and ends Saturday at sundown, the 7th day of the week.
The Jewish Sabbath is Saturday, from sundown on Friday until Saturday after dark.
Shabbat starts Friday at sundown and ends Saturday at sundown.
The Sabbath is the Jewish day of rest corresponding to the Christian Sunday. The Jewish Sabbath is from Friday sundown until Saturday after dark.
The weekly day of rest is the Shabbat, from Friday sundown until Saturday after twilight.Prayer:Jews pray three times every day of the year. On Shabbat the prayers are longer, but it is not the only day of prayers each week.
Jews pray three times on a regular day. Once at night, once in the morning, and once in the afternoon. Since Jewish days start at sundown, they are actually praying the first prayer of the next day.