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.

Who are called to repentance?
With what was He filled?
What high ideal should he placed before the young?
While God is merciful, does this clear the guilty?
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?
How fully has God promised to supply our needs?

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