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 will the gates of the heavenly city finally be opened?
What restriction did God make respecting marriages in Israel?
What will He then do for each one?
What endearing title is given the sixth church?
What does the Psalmist say of these chariots?
Is this chastening a pleasant experience?
In narrating the work of creation, what statement is made concerning its completion?

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