Lord our God, you were pleased to bring joy into the world through the Incarnation of your Son. Grant that we who honour his Mother, the cause of our joy, may always walk in the way of your commandments with our hearts set on true and lasting joy in you. (Prayer over the Gifts, Mass of the Blessed Virgin Mary)
Christ is our principal reason for happiness. He removes every trace from sadness from our hearts. Our Lady is truly the Cause of our joy, since her cooperation in the economy of salvation makes it possible for Christ to enter into us.
...The Blessed Virgin can show us how to be the cause of joy for others in our family life, at our place of work and in all our social contacts, our most casual encounters with acquaintances, our interviews and business trips. The brief duration of our meeting with neighbors does not matter ... Our own original source of joy is God, to whom the Blessed Virgin leads us.
On this fourth day of the Novena in honour of the Immaculate Conception we can examine the quality of our joy. Can others find God through our cheerful disposition? Are we uplifting -- do we bear charm not harm for those with whom we come into contact every day? Today we can offer Our Lady a firm and sincere resolution: May we make the way lovable and easier for others, since life brings enough bitterness with it already. Our cordiality is a way of imitating the blessed Virgin, who smiles on us from heaven as we brighten up the way of holiness for our fellow men. She encourages us to discover her Son in others.
Here is the novena for the fourth day.