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 do the heavens declare?
What is the evidence of genuine, living faith?
Can anyone boast of sinlessness?
In all we do, whose glory should we have in view?
What did He say to the two blind men as He healed them ?
How are the present effects and future results of chastisement contrasted?
What did the Lamb do with this book?

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