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.

How did He encourage His disciples to look for the fulfilment of prophecy?
In what two great commandments is the law of God briefly summarized?
What did Christ say would be the moral condition of the world just preceding His advent?
19. Will Satan and his agents attempt to counterfeit the coming of Christ, and work signs and wonders to confirm their pretentious claims?
What will be the difference between the portion of the righteous and the wicked?
Who is the seed to whom this promise was made?
What did John see concerning this city?

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