Living, as we do, with two opposing forces trying to gain possession of our souls, we often have thoughts and desires that we are tempted to turn into words and deeds.
When we have a questionable thought or desire, one way to determine its goodnes is to ask if it comes from God or somewhere else. Often, just asking the question: “Does this desire come from God?” is enough to let us determine its goodness.
As a general rule, the more consideration we have to give to the question, the less God wants us to do it.