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 may we determine the truthfulness of any doctrine ?
How did Jesus honor His parents?
What will occur when the Lord descends from heaven?
12. After the subjects of the kingdom have been determined by the investigative judgment, what is given to Christ?
What part of the law of God especially has the Papacy thought to change?
What will be the first plague, and upon whom will it fall?
At the pouring out of the seventh plague, what announcement will be made?

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