"3He that killeth an ox is as if he slew a man; he that sacrificeth a lamb, as if he cut off a dog's neck; he that offereth an oblation, as if he offered swine's blood; he that burneth incense, as if he blessed an idol. Yea, they have chosen their own ways, and their soul delighteth in their abominations." (Isaiah 66: 3)
The greatest need of man is righteousness, and a new life.
The world commonly believes that better behavior is the most important aspect, regardless of what we are thinking or feeling. Some even believe that if we do good, even if we do not want to, that is righteous in God's eyes.
The fact is that there is nothing that we can do to make ourselves righteous:
"They are all gone aside, they are all together become filthy: there is none that doeth good, no, not one." (Psalm 14: 3)
"But we are all as an unclean thing, and all our righteousnesses are as filthy rags; and we all do fade as a leaf; and our iniquities, like the wind, have taken us away." (Isaiah 64: 6)
Before this prophecy, Isaiah writes:
"In righteousness shalt thou be established: thou shalt be far from oppression; for thou shalt not fear: and from terror; for it shall not come near thee." (Isaiah 54: 14)
Furthermore, righteousness is a gift (Romans 5: 17) which we receive by grace through faith in Chris (Ephesians 2: 8-10)
As recorded above, God is not looking for people who go through the motions of offering sacrifices, yet have neither recognition nor respect for the God whom they sacrifice to:
"And Samuel said, Hath the LORD as great delight in burnt offerings and sacrifices, as in obeying the voice of the LORD? Behold, to obey is better than sacrifice, and to hearken than the fat of rams." (1 Samuel 15: 22)
God is looking for those who recognize their broken and contrite hearts, sensing their need for a new heart, a new life:
"You do not delight in sacrifice, or I would bring it; you do not take pleasure in burnt offerings." (Psalm 51: 16)
God promised to provide precisely that:
"3But this shall be the covenant that I will make with the house of Israel; After those days, saith the LORD, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people. 34And they shall teach no more every man his neighbour, and every man his brother, saying, Know the LORD: for they shall all know me, from the least of them unto the greatest of them, saith the LORD: for I will forgive their iniquity, and I will remember their sin no more." (Jeremiah 31: 33-34)
"And I will put my spirit within you, and cause you to walk in my statutes, and ye shall keep my judgments, and do them." (Ezekiel 36: 27)
We need a new heart, a new spirit, not just the right motions and actions.
Because of Jesus, and all that He did at the Cross, we have His Spirit, a new heart, and we can walk in His peace and righteousness.
Instead of bulls and goats, or the shedding of blood, there is only one sacrifice we give:
"By him therefore let us offer the sacrifice of praise to God continually, that is, the fruit of our lips giving thanks to his name." (Hebrews 13: 15)
We praise Him for He has given us a new spirit, a new heart, and a new life, from which new behavior flows.