Lex orandi, lex credendi, lex vivendi, "as we worship, so we believe, so we live."
Robert Royal and Fr. Gerald Murray discuss this on The World Over in the video (after the page break). It is well worth reflecting on during your Divine Mercy devotions today.
Love the Holy Mass. Approach the altar in fear and trembling and with deep gratitude, because to eat the Body of the Lord and drink His Blood unworthily is a disaster for your soul!