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 would make the death of Christ in vain?
18. What is said of those who live to see the deliverance from modern Babylon, and the restoration of the true gospel?
What is to be the fate of those who, instead of worshipping God, engage in this false worship?
What else did Jesus do on the Sabbath?
Have the worthies of old gone to their reward?
By what name is the fifth state of the church addressed?
How enduring is this kingdom to be?

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