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 positive assurance of the resurrection is given?
9. What testimony did the Apostle Peter bear concerning his experience on the mount of transfiguration?
What reason did Paul give for glorying in tribulations?
How should we sympathize with others in their sorrows?
From whom do all good and perfect gifts come?
Who is to reign finally over God's kingdom?
How may we obtain eternal life?

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