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 gracious promise does God make to His people?
What constrained God to give His Son to die for man?
What great truth therefore follows?
After creating man, what did God say?
How is sin defined?
How will this great event affect the world?
What promise was made to Abraham concerning the land?

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