Pure Heart is a term used by many different spiritual beliefs.
The Catholic Church and some other Christians use the term to name a condition near to Salvation. The Roman Catholic Church promotes its members to seek it and codified the required knowledge and practices within the Liturgy of the Eucharist – which serves other purposes as well. Teachings are provided in the Liturgy of the Word which involves reading and singing.
Catholic Purity of Heart may be achieved following the practices of a devout Catholic. Although effort and persistence is required, the fundamental assumption is that we all carry obstacles to God within our hearts. Overcoming them requires effort and assistance granted through prayer.
The process of achieving a Pure Heart is compared with the exodus from Egypt of the Jewish people.
Some have considered the mentioned and other parts of the "Liturgy of the Word" to contain esoteric teachings. In this context the mass acts as a continual Exorcism. Some compare these beliefs with the Upanishads of Hindu Literature. The related Practices recommended in the Yoga Pradipika mention to restrain from bad company, sexual relations, exhaustion and very cold baths.
References to the heart in this context are abundant in the Bible.