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 specific instance is mentioned by Peter?
By what means is sin made known?
What was Messiah to do during the seventieth week?
What is said of one who professes to know the Lord, but does not keep His commandments?
Where were the Ten Commandments placed?
Does God always see fit to grant our petitions?
Who is the seed to whom this promise was made?

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