Taking care of God's business
The reason I love this quote so much is that it reminds us of a key reality. We are stewards of God's things, not owners. We often find confusion about this fact in the Church.
People, and even priests, can come to think that they are the owners of apostolates, ministries, or a number of other realities. Or, they can feel that they own the liturgy, the doctrine, or the sacraments. It is not the case. Everything in the Church is focused on grace, which is a free gift of God. We cannot own it, as it goes far beyond our capacity.
God gives according to who he is, and we try to give back according to who we are. God is infinite and all-powerful. We are limited and weak. Nevertheless, God chooses to accept our efforts lovingly as a gift that builds a relationship.
When we recognize ourselves as stewards of the gift, rather than absolute owners, we are more likely to appreciate the greatness of the gift. As a priest, there are some details of the liturgy that I can decide, but most of it is determined by the rubrics. (rubrics is a technical term for what is like a rule book or manual)
This all leads to a fundamental attitude of humility, which is so helpful for us in our spiritual lives. God loves the humble and resists the proud. (cf. James 4:6)
When we accept that we are on God's business, we are filled with hope that he can do great things in us and become less worried and preoccupied about the results. Let go and let God!