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 complete was Christ's victory over death?
What does Christ declare Himself to be?
Who is this dragon?
What is the love of God declared to be?
Which day is the Sabbath?
Of what besides a knowledge of God as Creator, is the Sabbath a sign?
Who did he say he was?

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