When we think of detachment we immediately think coldness, loss, or indifference. It often seems to carry a negative connotation to it, that we will be without something that we had before. It can be so hard to let go of things that we are attached to--they give us comfort, security, and perhaps a sense of joy. The call to be detached, however, is a call to something higher, to rise above "things."
Detachment from this world, is an overwhelming attachment to God. The less we cling, the more openness we have to Him and His plans. Clenched fists denote an interior tension that is the complete opposite of surrender. The more we hold onto what we are afraid to lose, honestly the more unhappy we become. It puts the focus on our own satisfactions and serving ourselves and actually hinders our freedom.
The more we cling to God alone, the less we have to fear. The saints struggled and suffered and had times of sadness, but they were always full of joy. Their joy was not dependent upon externals or circumstances, but upon God, Who never changes and is always faithful. Their joy came from the interior conviction that they were deeply loved by Him and that would endure forever. Knowing you are loved, enables you to return that love--and that is detachment--love for the "one thing necessary."
We can all look at our lives and see something that we need to let go. Just think about what you are most afraid to lose and you will see what you need to surrender to Him. We can grow in detachment by thinking more about heaven, praying for the desire for the beatific vision, and living as if we were already in eternity. This does not mean that we ignore the present duties and stresses that we have to face, but that we meet them head on and embrace everything, knowing that we are passing through this world as travelers on the way to Him, Who we know loves us.