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 is Christ to one renewed after God's image?
For what purpose is the mystery of the gospel made manifest?
Of whom was Christ to be born?
What special reason is given for this?
What does the prophet Isaiah, speaking for God through this Spirit of Christ, call the seventhday Sabbath?
What scene in heaven was presented to the prophet as the seventh trumpet was about to sound?
How perfect will be their knowledge of God?

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