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 is the means through which this justifying grace is made available to the sinner?
What is revealed by the law?
What fate awaits blind teachers and their followers?
What will occur when the Lord descends from heaven?
What besides creation were Israel to remember when they kept the Sabbath?
What does He know and remember?
What does Daniel say of this kingdom?

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