People interpret 'bless all the people pure in heart' are misinterpreting the phrase as a call to be perfect. According to the Pharisees, even Jesus was not pure enough. People striving for perfection are not only striving for perfection on the outside, but also on the inside. 'I'm not good enough, I'm not pure enough, I don't pray enough, I don't give enough.' It's in the heart of the person where purity must begin.