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 futile is it to attempt to hide sin from God?
Through whom is this reconciliation made?
What first attracted the prophet's attention?
How does the Sunday law of Charles 11, of 1676, read?
With what do these trumpets deal?
For what did Job say he would wait after death?
What did Christ say concerning secret prayer?

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