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 saved the people from the predicted overthrow?
What power is there in the blood of this covenant?
Who is Lord of the Sabbath?
Is this chastening a pleasant experience?
Does Jesus sympathize with us in our afflictions?
What reward awaits the true child of God?
What has Christ promised the overcomer?

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