God was the first to sacrifice. He sacrificed an animal to clothe Adam and Eve and with this, He showed us the way to a beneficial faith. Just as love demands attitudes of sacrifice, so does faith. In the past, no hero of faith conquered anything without the use of faith with sacrifice. Abel is one of the greatest examples of this; he was considered righteous before the Most High just because of his sacrifice.
Jesus taught us sacrifice when He said:
"If any man will come after me, let him deny himself, and take up his cross, and follow me." Matthew 16:24