Speaking through the prophet, Hosea, God said this to His people.
For I desire mercy, not sacrifice,
and acknowledgment of God rather than burnt offerings.
There was a serious problem among God's people at the time Hosea recorded those words. They were observing all the ceremonial aspects of the law of Moses, but they paid little heed to God's commands to love Him and their neighbors. They would sell their brethren into slavery for a pair of sandals if they needed to without mercy or any thought of kindness. They used the poor among them and stole from them without pain of conscience.
Such was the moral fiber of these people. They were doing as they pleased from a moral standpoint, but they thought they were forgiven for their bad behavior simply because they continued to offer the prescribed sacrifices. They were, after all, God's chosen people. He would not discard them.
They were wrong.
God has always preferred obedience and mercy and forgiveness over sin and sacrifice. He has always preferred relationship over superstitious kowtowing. His people were not having it and so He judged them and sent them into captivity.
None of this was happening in Hosea's time. His people eventually paid for their failure to live in relationship and obedience to their God. Mercy and acknowledgement of God was not forthcoming from these people.
Many years later,
after the captivity when God's people had returned to the land of their
forefathers, God sent them Jesus. Jesus tried to teach them and
especially their spiritual leadership many things. Jesus quoted this passage to the pharisees when they accused him of hanging around with tax collectors and sinners. Here is an excerpt.
10 While Jesus was having dinner at Matthew’s house, many tax collectors and sinners came and ate with him and his disciples. 11 When the Pharisees saw this, they asked his disciples, “Why does your teacher eat with tax collectors and sinners?”
12 On hearing this, Jesus said, “It is not the healthy who need a doctor, but the sick. 13 But go and learn what this means: ‘I desire mercy, not sacrifice.’[a] For I have not come to call the righteous, but sinners.”
This is what God means when He says He desires Mercy over sacrifice. He wants to show us His mercy and His grace and He wants to be in relationship with us and heal us. All we have to do is love Him and love our neighbors. He wants the best for all of us, but He cannot help with that if we have our own sense of righteousness that does not derive from Him.
I think we in the Church are many times guilty of behaving like ancient Israel. We may not sell our brethren for a pair of sandals, but how often do we turn our backs on the unsaved because they are not 'moral enough' to hang around with us righteous folks?
We are all sinners my friend. We all need forgiveness and grace from the One True Source. It's the only way we will ever be anything even approaching righteous. So Christian, next time you are riding the high righteous horse and thinking you are carrying the sword of the Lord, have some mercy and grace instead. Your heavenly Father will remember it and bless you in eternity. Love as Jesus loved. Give as He would give. Never forget what it took to save you and then you will know why God prefers mercy to sacrifice.