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 was the Comforter to do when He came?
What is the last book of the Bible called?
What was this earthly sanctuary and its round of service?
How does David speak of Christ's coming?
With what are we to comfort one another?
In what language is the same truth again expressed?
What is written on these gates?

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