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.

How complete is the salvation obtained in Christ?
Why did God confide in Abraham, and commit sacred trusts to him?
Who will thus he judged by the saints?
What else did Jesus do on the Sabbath?
By what authority was Sunday Sabbath-keeping instituted?
23. Just preceding Christs second coming, what solemn decree will go forth showing that the cases of all have been decided ?
What encouragement is held out concerning the branches which have been broken off?

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