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.

To what parts of the ancient armour is faith compared?
14. What was the next step in their plan to secure lawful authority to carry out their unlawful purpose?
Is there danger of delaying correction too long?
What did the prophet see in this vision?
What, more than all else, proves the perpetuity and immutability of the law of God?
Under what authority were its decrees published?
By what have these things been revealed to us?

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