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 is the great purpose of Christ in His work of reconciliation?
24. In what prayer for those who crucified Him did Christ manifest the true spirit of the gospel-love for sinner?
At the conclusion of Daniel's prayer, what assurance did Gabriel give him?
21. To what extent is the apostasy, or fall, of modern Babylon, the mother, and of her daughters, to be carried?
Upon what one fact does Paul base the Christian hope?
Will even this terrible judgment lead men to repent?
To whom did Jesus first send the twelve disciples?

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