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.

By what means is this healing accomplished?
Of what were the works of Abraham an evidence?
With what words did God admonish Cain?
Why did the Lord abhor the Canaanites?
What power is there in the blood of this covenant?
6. How did they manifest their displeasure at His healing the man with the withered hand on the Sabbath?
What does the Apostle Paul say concerning this?

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