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 complete was Christ's victory over death?
What reason is given for Gods readiness to forgive sin?
What prayer did Moses offer in behalf of Israel?
What change is thus brought about?
What solemn charge was given him concerning his public work?
Who is this dragon said to be?
What instruction does the Apostle John give touching this subject?

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