Jacob and Esau had no “original sin” becuase they had not done anything good or evil. If they had original sin how could anything be by promise?
Days and Years in scripture:
whyprophets.com/prophets/day_year.htm
Genesis 5 – the genealogies frequently say “the days of (name) were (x) years.” Days and years seem to be interchangeable.
Genesis 29:27 – Jacob served “a week” for Rachel, meaning seven years.
Exodus 20:10; Leviticus 25:3-4 – a seventh day Sabbath is paralleled by a seventh year Sabbath.
Exodus 13:10 – the annual Passover should be kept “from days to days.” Similar wording is used regarding years in Numbers 9:22, Judges 1:40, 1 Samuel 1:21, 1 Samuel 2:19, 1 Samuel 27:7 and 1 Kings 1:1. English translations often change these references to say “year” or “years.”
Numbers 14:34 – The children of Israel wander in the wilderness for forty years, to correspond to a previous forty day period.
Ezekiel 4:5-6 – This is probably the key text, since it deals specifically with predictive prophecy. Ezekiel is given a prophecy for the people, where every day is to symbolize a year.
(LDS readers should also compare JST Revelation 12:5 with KJV revelation 12:6.)
NOTE: Calvin also translated Days in Rev 12:6 as years just as JS did.
Where a “Day” Represents a “Year” in Daniel:
Daniel 1:5, 18 – the end of Daniel’s three years’ training is referred to as the end of his “days.”
Daniel 8:26 – many years in the future is described as “many days” in the future.
Daniel 9 – the “seventy weeks” prophecy, even before we see its literal fulfillment, only makes sense if a “week” is seven years. In fact, the Hebrew word for “week” is just “seven.”
In the light of the above, it seems entirely reasonable that Daniel’s “days,” when in the context of “end of the world” predictions, can be read as “years.”
Similarly, the 42 “months,” given that they equal 1260 “days,” should be seen as 42 groups of 30 years (the ancient Jewish month had 30 days). And the “time and times and dividing of a time,” since “a time” can be translated “a year,” and 3 1/2 years contain 42 months, could be treated in the same way.