Thinking on death is the most profitable meditation we can make.

Indeed, Our Lord's most holy passion and death offers us the greatest meditation, but pondering our own imminent death can bring us great fruit as it prepares us for the most important thing we will do: enter into eternity.
"Remember man that you are dust, and to dust you shall return." By meditating on their deaths, many have renounced this fleeting world for the monastery and cloister. By meditating on their deaths, many have conquered the flesh, the world, and the devil. By meditating on their deaths, many have climbed the ladder of holiness in a brief time. To keep death daily before your eyes is one of the greatest secrets to sanctity, for death is the only certainty in this life. And those who ponder the hour of their death daily will not be surprised when that moment comes; rather, they will have prepared for it their entire lives and will be ready to meet their Creator. In this soul-jarring work, Thomas à Kempis guides the reader to consider the last four things: death, judgment, heaven, and hell. One of the devil's favorite words is tomorrow. But God's is today. Meditations on Death is like a mini-retreat that will redirect your heart to eternal things rather than passing things. For to contemplate the hour of your death is to already have one foot in heaven.