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 indwelling Power keeps such from sinning?
Into whose name are believers to be baptized?
What is the means through which this justifying grace is made available to the sinner?
What does this angel say?
If one professes to abide in Christ, how ought he to walk?
What did God do in the beginning on the seventh day?
What sign was to follow the darkening of the sun and the moon?

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