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 Christ make it clear to them that the Scriptures testify of Him?
Through whom is this reconciliation made?
What words of Peter seem to indicate another outpouring of the Spirit?
What were these stones to commemorate?
When did the moon refuse to give her light?
What is our duty toward the outcast and wandering?
What promise is made to them that walk uprightly?

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