To do righteousness and justice is more acceptable to the Lord than sacrifice. (Proverbs 21:3 ESV)
During the era of Old Testament sacrifices, an individual with more possessions would be able to offer more sacrifices to the Lord than the person who had little. In 1 Samuel 15 we have the account of King Saul being reprimanded by Samuel for trying to be acceptable to the Lord by sacrifice and not by doing righteousness and justice. He was told to utterly destroy the Amalekites in a war. Saul did destroy most, but kept alive Agag the king, and the choicest sheep, oxen, and spoil of the land. When Samuel confronted Saul about this, he said he kept the choicest spoil of the land so he could sacrifice to the Lord your God at Gilgal (1 Samuel 15:21). Samuel said:
“Has 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 listen than the fat of rams." (1 Samuel 15:22 ESV)
If you have ever been tempted to work longer hours so that you would have more money to tithe, you have just fallen into the same trap as Saul. If you have ever done wrong during your business practices because profit drove you as oppose to righteousness and justice, you have just become less acceptable to the Lord. Jesus is seeking to mold us into a certain type of individual, one who does righteousness, justice, and obeys the voice of the Lord; for that is more acceptable to the Lord than sacrifice.