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 are the Scriptures able to do for one who believes them?
In what song of praise did a host of angels join?
Who were brought to Him for healing?
From what is He able to keep us?
What is the value of proper early instruction?
When had God said this?
Whom does Paul say the saints are to judge?

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