Jesus now specified two examples of the Pharisees' spiritual myopia (vv. 42-43), and then He compared them to something similar that defiles (v. 44). Jesus announced His condemnation with the use of "woe."
11:42-43 The Pharisees typically tithed scrupulously, even their garden herbs two of which Jesus specified (cf. Lev. 27:30-33; Deut. 14:22-29; 26:12-15). This was proper, but they neglected giving more important things to God including justice and love. Normally the leaders of the synagogues occupied the front seats, so Jesus was criticizing the Pharisees' love of position. Respectful greetings in public places pandered to their pride too.
11:44 The Pharisees scrupulously avoided touching graves to avoid ritual defilement. However they themselves defiled other people who contacted them as hidden graves defiled those who unknowingly walked over them (cf. Num. 19:16). While trying to remain ritually pure themselves, they were defiling many other people who were unaware of the Pharisees' evil influence on them. Their sins contaminated the whole nation.