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 did he tell them to do?
Because of this, what is Christ able to do?
After the law had been proclaimed from Sinai, what did the people again say?
Of what is the Sabbath commandment a part?
How, according to Luke, did Christ answer this question?
In order to grow by the Word of God, what must one do?
How perfect will be their knowledge of God?

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