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 revealed in the gospel?
In what literal language is this persecution of the people of God further described?
18. In what statement was Christ promised as a Savior and Deliverer of the race as soon as sin entered?
What trying experience did Christ then foretell?
What question did the disciples ask Christ concerning His second coming?
When did David say he would be satisfied?
What has been promised in order that man may be redeemed from this condition?

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