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.

How does David express this same truth?
By whom were the heaven and the earth created?
Before His birth, what did the angel say to Joseph concerning the naming of the child?
Who does the apostle say saw Christ after He was risen?
15. What commands obeyed would bring about a peaceful solution to this wide-spread and growing conflict?
Why did God give His only begotten Son to the world?
To whom is the gospel the power of God unto salvation?

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