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.

In what event was this prophecy fulfilled?
For what did David pray?
What restriction did God make respecting marriages in Israel?
What was Satan's design in thus persecuting the church?
What did Charlemagne's Sunday law of 800 require?
Has the exact time of Christ's coming been revealed?
Of what are the streets of the city composed?

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