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.

How did He further explain the new birth?
What is the great purpose of Christ in His work of reconciliation?
What will God allow to come to those who reject truth?
What words of Peter seem to indicate another outpouring of the Spirit?
When this sign appeared, what were the disciples to do?
What is set forth as the basis for hope and comfort?
Under whose influence are the nations to be assembled?

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