How early was this sacrificial system known?

Answer

"By faith Abel offered unto God a more excellent sacrifice than Cain, by which he obtained witness that he
was righteous, God testifying of his gifts." Heb. 11: 4. See Gen. 4: 3-5; 8: 20.

What would make the death of Christ in vain?
With what did He say they would he baptized?
Who opens the judgment and presides over it?
On which day was a double portion of manna gathered?
Why was Christ declared worthy to open these seals?
Where do the dead sleep?
In the new earth, what will he no more?

Questions & Answers are from the book Bible Readings for the Home Circle