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 are fitting inquiries for those convicted of sin?
What positive assurance of the resurrection is given?
What did some of the people do on the seventh day?
What definite period is mentioned under this trumpet?
What accompanies the earthquake?
If one lacks wisdom, what is he told to do?
In what one promise are all these promises summed up?

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