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.

What did Jesus say of the one who loves Him?
With what was He filled?
With what promise do the Old Testament Scriptures close?
Who first enjoined Sunday-keeping by law?
Why, under these plagues, does the Lord give men blood to drink?
What will he receive who endures temptation?
What peaceful condition will prevail in the earth made new?

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