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.

16. How did Christ reprove those who, though familiar with the letter of the Scriptures, failed to understand them?
What did He say a little later to the eleven?
What question did -Christ's wonderful teaching call forth?
What high ideal should he placed before the young?
What proves that the law is an undivided whole?
What example did Christ set in Sabbath observance?
What scriptures show that Christ's coming will be a time of reward?

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