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 application did Jesus make of this prophecy?
How does Abraham's experience show that obedience and faith are inseparable?
In what prophecy was the work of reconciliation foretold?
What reason is assigned for the fall of Babylon?
Does the first commandment show who the author of the law is?
How long is Satan to be imprisoned on this earth?
What precious promise has God made to His children?

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