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 is Christ's second coming described in the Psalms?
What different results attend the covering and the confessing of sins?
What is promised those who honor their father and their mother?
21. What shows that the new, or second, covenant and the Abrahamic covenant are virtually the same?
Is Christ coming again?
When did David say he would be satisfied?
Whose prayers does Solomon say are an abomination?

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