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 whose image was man created?
What reason is given for Gods readiness to forgive sin?
How closely are righteousness and life thus united?
What was He to take away in the midst of this week?
Can there be sin where there is no law?
Through whom did God create the world?
After resting on the seventh day, what did God do?

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