We say that to 'give up all evil and to develop the good' is the heart of the Buddha's teaching. If we only make merit but have not stopped doing bad things, then we will never have a day of completion. It is like an overturned bowl which is left outside in the rain. Even if the water is falling right on it, it only touches the outside and not the inside. In this way the bowl will never get full. - Ajahn Chah