You should have paid your tithes while at the same time observing the other aspects of the law. We pick up where we left yesterday, as we see Jesus continuing his chastising of the Pharisees and other religious enthusiasts. He is particularly interested in opening their eyes to the knowledge of the fact that they are responsible for everything that has become wrong with their religion (honoring God only with the lips while the heart is far from God [cf. Mark 7:6-7]). As we heard in yesterday’s Gospel reading, the religious leaders had become so much obsessed by the externals to the detriment of the tenets of their religion (cf. Luke 11:37-40). Their obsession with the ‘accidentals’ of their religion had turned them into religious police, ready to pounce on transgressors or those who failed (or forgot) to observe with strict adherence the prescribed “externals.” 
That Jesus refers to such individuals as hypocrites is not meant to belittle or downplay the relevance of the offices that they occupied. Jesus recognized their call as leaders and respected the authority of their offices (cf. Matthew 23:2). But he was also aware that, as leaders, there was a responsibility to which they were not only called but for which they were held accountable as well. This responsibility, Jesus argues, does not begin and end with the mere (literal) observance of the law (letter of the law). Rather, it extends to, and includes the law's moral interpretation (spirit of the law) too: " It is wonderful that you pay your tithes, and it is even more wonderful that you pay them honestly," Jesus tells them. " However, that is only part of the observance of the law. The other part that you do neglect, and which is equally important, is to act towards your brothers and sisters with mercy and charity, for this is the only way you will remain faithful to the law." 
The Pharisees, Scribes, and other religious leaders were hypocrites, not because they were pretending to be what they are not, but because they had failed to uphold the interpretation of the law. They had failed to live up to the expectations of both the law and their offices (positions). They were hypocrites because they had refused to learn what the law says in order to put it to practice.