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 does God design that His Word shall be to us in this world of darkness, sin, and death?
Who alone comprehends the things of God?
Of whom did Christ say the Scriptures testify?
In what age of the world is disobedience to parents to be especially manifest?
To whom, then, should its observance be rendered?
But are not the righteous dead in heaven?
What does Christ give His followers?

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