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.

Why cannot the natural man receive the things of the Spirit?
What is said of the stability of God's character?
4. What was another memorial instituted to commemorate another signal providence in behalf of the Israelites?
What did God do in the beginning on the seventh day?
What appeared upon the opening of the second seal?
What protection has God promised His people during the seven last plagues?
Whom will they be like?

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