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 followed immediately after the gaoler and his family had accepted Christ as their Saviour?
Following one of His parables, what did Christ say?
To whom was Belshazzar's kingdom given?
18. What is said of those who live to see the deliverance from modern Babylon, and the restoration of the true gospel?
What, according to prophecy, was to be Christ's attitude toward the law?
What gives us the victory in our conflict with the world?
What promise was made to Abraham concerning the land?

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