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 witness does the true believer in Christ have that he is accepted of God?
For what is all Scripture profitable?
What restriction did God make respecting marriages in Israel?
What is one way in which a child may dishonor his parents?
In what instruction did He emphasize the importance of keeping the law?
Who first enjoined Sunday-keeping by law?
Is there danger of believers losing their hold on Christ?

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