How can you explain Matthew 12:7? Doesnt it say that God offers mercy and not sacrifice? How, then, can Jesus be the Sacrifice?
As a general rule, when one finds what might appear to be a contradiction in the Bible, the first thing to do is to look at the context of the passage in question. In this case, it is a good idea to go to the passage Jesus is quoting from. This is Hosea 6:6. In Hosea, God is telling his people that what he desires is not for them to simply go through a ritual sacrifice without the heart and the faith which is what he really wants. In other words, although God clearly wanted the Jews to make the sacrifices he had commanded, if they simply went through the motions but did not give God true devotion and faith, then the sacrifices, by themselves, meant nothing. If we go to church and do all the right things, but do not forgive our brother, then it is all meaningless and we are not going to be saved (Matthew 18:21-35, especially v. 35). Jesus sacrifice is not sufficient if we do not respond with the right heart, and going through a ritual does not solve the problem.
The idea is also found in several other Old Testament passages. The most well known is Psalms 51:16. "You desire mercy, not sacrifice, or I would bring it; you do not take pleasure in burnt offerings." One could argue that David is exaggerating here. In other words, there is no question that God wanted the Jews to make sacrifices and to bring burnt offerings. This was commanded by God in Leviticus. David is pouring out his emotions here. Let us not take him literally. Let us not take Jesus literally in Matthew 12:7 or Hosea literally in Hosea 6:6. Like David says in Psalms 51:17,
"The sacrifices of God are a broken spirit; a broken and contrite heart, O God, you will not despise." In other words, although God clearly commanded and wanted sacrifices from the Jews, and although obviously no one is saved at the present time without the sacrifice of Jesus, what God wants from us is not to say the right words and do the right actions, but to give him our hearts, our faith and to treat others with love and forgiveness, as God treated us.
Another example is Jeremiah 6:20 in which God says to his people that their burnt offerings are not acceptable–that they do not please him. Ritual without the right heart is not only not pleasing to God, it makes him angry. The sacrifice is not the problem. Indeed, "without the shedding of blood, there is no forgiveness." (Hebrews 9:22), but this is not the subject of Matthew 12:7, Hosea 6:6, Psalm 51, Jeremiah 6:20 and many similar passages.
So, Matthew 12:7 is definitely not teaching that the sacrifice of Jesus is not important or necessary. That is not what Jesus is talking about. He is talking about what God wants from us, which is not legalistic obedience, but a contrite heart and to treat others as he treats us.
John Oakes, PhD