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.

When David confessed his sin, what did he say God did?
29. What bears witness to the genuineness of the righteousness obtained by faith, apart from the deeds of the law?
After receiving a knowledge of the truth, what must one do in order to be sanctified by it?
10. What are those to drink who accept the teachings of Babylon, and thus render homage to the beast?
Who will sing the song of Moses and the Lamb on the sea of glass?
Can man of himself, unaided by Christ, keep the law?
Whom does the Lord chasten?

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