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 accompanies repentance?
What result is to be obtained by the exercise of the gifts in the church?
How did Christ treat His Father's commandments?
What was the character of- their deeds?
What is it that makes a thing holy?
What will this power propose that the people shall do?
To whose authority are the angels subject?

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