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.

For what is all Scripture profitable?
What admonition is therefore given?
Why did the Lord destroy Sodom?
Through whom did God create the world?
Why did God give His only begotten Son to the world?
Why was this to be?
What will finally he the privilege of God's children?

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