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.

Why did Christ tell us to love our enemies?
Who did He say would be called great in the kingdom?
When God was about to proclaim His law to Israel, of what did He tell Moses to remind them?
14. Besides telling His disciples when to flee, how did Christ further show His solicitude and tender care for them?
How did Christ Himself say He would come?
Are the angels interested in the plan of salvation?
How did Job treat the poor?

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