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?
28. BY what miracle and phenomenon in nature did God indicate the character of the deed which was being committed?
How long will the saints engage in this work of judgment?
When asked which commandments, what did Jesus say?
By what authority was Sunday Sabbath-keeping instituted?
25. Since the Sunday Sabbath originated with the Roman power (the beast), to whom will men yield deference to compulsory Sunday laws?
6. Looking forward to the conflicts through which His followers must pass, what cheering message did Christ send them through the Apostle John?

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