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 is the love of God supplied to the believer?
Upon what ground were the previous promises then renewed to Abraham?
What is said of his mother and his grandmother?
Under what threatened penalty is the worship of the image of the beast enforced?
What was the character of- their deeds?
What means will be employed to compel all to receive this mark?
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