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?
In what was shown the first tangible evidence of this \"falling away\" from the truth of God?
What, then, is the nature of all Sabbath legislation?
To what place were the angels that sinned cast?
Upon what conditions are we promised needed blessings?
What classes are we especially enjoined to help?
How long will they possess the future kingdom?

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