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.

Upon what ground does God's work for sinners rest?
What is required besides a belief in the existence of God?
In what promise was a Saviour from sin first revealed?
To what insults was Christ subjected at the house of the high priest?
14. What does the \"psalm for the Sabbath day\" suggest as proper acts and themes for thought and meditation on the Sabbath?
What influence has this hope upon the life?
What is an evidence of perfection?

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