O how happy and blessed are those who love the Lord and do as the Lord himself said in the gospel: You shall love the Lord your God with your whole heart and your whole soul, and your neighbor as yourself. Therefore, let us love God and adore him with pure heart and mind. This is his particular desire when he says: True worshipers adore the Father in spirit and truth. For all who adore him must do so in the spirit of truth.
From a letter written by Saint Francis of Assisi