Singing is one way through which man use to express his feelings and becomes in Christian liturgy a way of dialogue with God. To underline the importance of the music in religious life, the author makes a short historical incursion starting with Old Testament and ending with the latest documents of the Church. After this incursion, the study makes distinction between liturgical, religious and sacred music. Music has to fit in liturgy, to express the characteristics of Church: internalness, unity and communion. Religious music has to offer the means to express, to live, to transform the liturgic life into pray.