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 for Christ to go away?
12. What universal boycott is to be employed, in an attempt to compel all to receive the mark of the beast?
What similar charge was brought against the Apostle Paul?
On what day was John in the Spirit?
Against what deceptions did Christ then warn us?
Out of what will they be judged?
Who will dwell with the redeemed?

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