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 great exchange has been wrought for us in Christ?
What did Christ say of those who rejected John's message?
To whom did Christ become the author of salvation?
How diligently should parents teach children God's Word?
What reason is given in the fourth commandment for keeping the Sabbath day holy?
What else has He promised to do?
With what were many possessed in Christ's time?

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