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 basis of faith?
By what name is Christ appropriately called?
What great exchange has been wrought for us in Christ?
Under what threatened penalty is the worship of the image of the beast enforced?
For what will the heathen he assembled in Palestine?
What did Christ learn through suffering?
Who is the seed to whom this promise was made?

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