The Sermon on the Mount is teaching for life, the Our Father is a prayer; but in both the one and the other the Spirit of the Lord gives new form to our desires, those inner movements that animate our lives. Jesus teaches us this new life by his words; he teaches us to ask for it by our prayer. The rightness of our life in him will depend on the rightness of our prayer.
Source: Catechism of the Catholic Church (Vatican.va)