When does the Sabbath Begin according to Scripture?

According to the Bible, the Sabbath takes place on the seventh day of a week, which historically is always on Saturday.  Some International bodies and groups that wish to hide this Truth, seek to change times and laws, organize and push consensus to codify Sunday as the seventh day of the week (ISO 8601); and through their power of global governance they also make use of the "internet of things" as a tool for digital book burning and hiding Truth.  The Christian church went astray a long time ago making their corporate day of worship after a sun god, thanks to the Roman Emperor Constantine in 321ad, "Sol Invictus."  For thousands of years and as shown in Jewish tradition, Saturday has always been known as the Sabbath Day.  Even in Roman writings, such as Cassius Dio's Epitome of book 65 he writes about the destruction of Jerusalem in 70ad, and states that it occurred on Rome's "Saturn's Day", which is where the modern name came from.  Of course, the Jews do not worship Saturn, and they only call this day the seventh day (Shabbat  שַׁבָּת ).  This seventh day has been a perpetual and serial counting of 7 days since God's first week of creation.  This serial counting and pattern has never strayed from its course that God set, and (if God has anything to say about it) it will always continue into the future for eternity.  This 7 day serial counting has nothing to do with its placement or numbering on a Calendar, whether it be a Roman calendar or Hebrew.  The pattern remains 1, 2, 3, 4, 5, 6, 7 and repeats in perpetuity.   However, the exact time period this day is kept by the Jews according to their tradition has changed since their Babylonian captivity between 598 and 538 bc compared to what it specifies in the Bible, which is from Dawn to Dawn, not Evening to Evening.  Therefore, as many places in the prophets explain, such as the book of Amos, the Jews have a polluted Sabbath which is an abomination to God.  It is important that true believers in God get this time and day right as they seek to Obey Him in Spirit and Truth.  

For additional information read the  Day Dawning document

Or the Fentiman-Travis Study (111 page breakdown)