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 are the evidences that one has been born of God?
To what place did Christ carry these sins?
Concerning what subject ought we to be informed?
On what did God write the Ten Commandments?
6. In His reply, how did Christ indicate that neither the end of the world nor of the Jewish nation was immediately at hand ?
Where will all the saints then go?
What reason did Paul give for glorying in tribulations?

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