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.

Upon what basis has Christ taught us to ask forgiveness?
18. What effect did Christ's miracles have upon the individuals restored, and the people who witnessed them?
Was it possible for Christ to be holden of death?
What is said of one who robs his father or his mother?
What did this power do to the truth?
Whose sovereignty is thus challenged?
How fully has God promised to supply our needs?

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