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.

To how many is the Lord good?
How should the youth he taught to regard the aged?
I. What is said of the fifth commandment?
Why were the Sacred Writings given?
What admonition is therefore given?
How do those with renewed hearts and minds regard the commandments of God?
Was the Sabbath designed to be a day for public worship?

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