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 message of entreaty has God sent to us through His appointed messengers?
By what should we test, or prove, all doctrine?
With what was He filled?
How did Christ answer him?
On what day did the Jews meet for worship?
What is Christ's message to the last church?
For whom did Christ teach us to pray?

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