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.

Into what relationship to God does His love bring us?
13. What did John the Baptist say to the Pharisees and Sadducees when he saw them come to his baptism?
What is the ground of justification on God's part?
29. What statement immediately following the announcement mentioned in Rev. 22: 11, indicates that a judgment work had been in progress before Christ comes?
Did angels exist before the death of any of the human family?
In what work are angels engaged?
What will then he the condition of all the earth?

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