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's character preclude Him from doing?
What do transgressors bring upon themselves?
Of what kind of doctrines should we beware?
Upon what ground were the previous promises then renewed to Abraham?
What did the devout Simeon say when he saw the child Jesus?
What question did -Christ's wonderful teaching call forth?
In what condition did David expect to rise?

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