See Poole on "Matthew 23:23". There are two great notes of hypocrites:
1. To be more exact, in and zealous for the observation of rituals and the traditions of men, than in and for the observation of the moral law of God.
2. In matters of morality, to be more exact and strict in and for little things, than for things more grave and weighty. There is no commandment of God so little as we may neglect, or despise, or disobey it; but yet there is a difference in duties, and we ought to have more regard to the greater than to the lesser.