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.

Why was it necessary to make this atonement?
29. What statement immediately following the announcement mentioned in Rev. 22: 11, indicates that a judgment work had been in progress before Christ comes?
What reason is given in the fourth commandment for keeping the Sabbath day holy?
What is Neander's conclusion regarding this theory?
What false idea of this gathering were some to hold?
How does Isaiah speak of the wicked at this time?
Do they take any part in earthly things?

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