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 great exchange has been wrought for us in Christ?
At His birth, what message did the angel bring to the shepherds abiding in the field?
After giving instruction by the use of parables, what question did Christ ask His disciples?
What special reason is given for this?
Whom are all called upon to worship?
What is the love of God declared to be?
Under the old covenant, what did the people promise?

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