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 leads sinners to repentance?
How did the father show his joy at his son's return?
In what condition was the world before the Flood?
Does the Papacy acknowledge that it has changed the Sabbath?
In what words did He foretell its destruction?
What will be the final doom of Satan and his angels?
When Christ sent out the seventy, what did He tell them to do in the cities whither they went?

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