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 explains God's apparent delay in dealing with Sin ?
Of whom was Christ to be born?
Why. should fathers not provoke their children to anger?
After she became queen of Persia, how did Esther show her integrity to God?
12. After the subjects of the kingdom have been determined by the investigative judgment, what is given to Christ?
What will the world be doing when Christ comes?
For what purpose did God give His Son to the world?

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