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 change is thus brought about?
To whom did Christ become the author of salvation?
To another whose sight He had restored, what did Christ say?
What is the first -symbol of Revelation 13:9?
What famine will come at this time upon those who have rejected God's messages of mercy?
How often did David say he would pray?
15. Because Solomon asked for wisdom rather than for long life and riches, what besides wisdom did God give him?

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