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.

By what other title is the Comforter designated?
How enduring is the moral law?
In this covenant with Israel, what obligation was imposed upon the people?
What reason is given in the commandment for keeping the Sabbath day holy?
How enduring did He say the law is?
What did it lead Moses to do?
Under what condition does the Lord not hear prayer?

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