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.

To whom is our worship justly due?
What reason is given for Gods readiness to forgive sin?
How perfect is the unity into which believers are brought by being baptized into Christ?
How did Jesus show His loyalty to God?
What was Satan's design in thus persecuting the church?
How visible is His coming to be?
How must one ask in order to receive?

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