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.

In what act especially has Gods love been manifest?
What did Jesus declare God's commandments to be?
And how should husbands regard their wives?
For what reason is worship justly due to God?
At His ascension, what assurance was given of Christs return ?
What promise was made to Abraham concerning the land?
Of what are the streets of the city composed?

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