For thou, Lord, art good, and ready to forgive; and plenteous in mercy unto all them that call upon thee.Psalm 86:5 (KJV)
It is easy to look at the New Testament as a book of mercy and the Old Testament as turmoil and strife, but we must understand that our Father in Heaven has shown mercy from the beginning of His Creation. In this psalm we learn that forgiveness before Christ came when men would follow and call upon God for mercy. He knows our hearts. He knows our flaws. He gave His Son as the sacrifice because He is merciful and knows that we are unable to bear the burden of our own sins.