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.

On what basis is there no possibility of justification for the sinner?
What was the special message for Noah's day?
Who has borne our sins, and stands ready to help us?
Against what evil should fathers guard?
When, according to prophecy, were men to amass great wealth?
Are the angels interested in the plan of salvation?
What experience followed this trust in Jesus?

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