These two words might seem out of place in a discussion of the spiritual life, but over the years I have come to appreciate a certain sort of selfishness and a certain practice of ruthlessness in the Christian life.
A spiritual director once told me that the spiritual life demands a particular selfishness; we have to make the sanctity to which God calls us as individuals an absolute priority. It's like when people in recovery say, 'nothing comes before my sobriety.' We have to say that nothing comes before our prayer, devotion, and daily right effort to follow in the footsteps of Christ. This doesn't mean that we ignore the requests and demands of people we love, people to whom we are committed by circumstance or state of life, or even strangers. But it does we mean that we discern these relationships carefully and ask ourselves if the time and energy we give to others are demanded by charity and justice, or if what goes into the relationship is a distraction. This can be very difficult, as most relationships mix both; in some ways they give glory to God and lift us up, and in other ways we conspire with each other to commit the distractions and dissipations of gossip, detraction, and the enabling of destructive behavior and sin. When someone gets selfish about sanctity, his refusal to participate in these comfortable sins of ordinary human interaction will earn him accusations of being conceited or proud. This can be a terrible loneliness and a difficult cross to bear and though I have not yet made a beginning of this myself, I pray for the grace of accept this burden with joy. "Blessed are you when they insult you and and persecute you and uttery every kind of evil against you because of me." (Matthew 5:11)
the spiritual life also demands ruthlessness with self. Patterns and habits of thought and action and ways of relating must be subjected to intense scrutiny. From our ways of praying all the way down to the manner in which we do the plainest activities of daily living, all must be examined to see if they give glory to God or distract us from our vocation to holiness. This can be very difficult, and when someone consents to be converted to God he usually has no idea what he is getting into. When the Holy Spirit finds a soul willing to work, the work will arrive. God is a jealous lover, and wants the whole person--the "whole person" being more than we even know of ourselves in the consciousness we have in this life. When a soul is asked to let go of habits and to adjust the patterns of external life it seems like the hardest ascesis there could be. But this is nothing compared to the work of the Holy Spirit in converting our maladaptive habits of heart and mind. It is one thing to let go of things and activities that we thought we loved, but it's quite another to begin to let of internal habits and dispositions, things we thought were our very self. But who we really are is hidden in God. We must be ruthless in this process and ready to let go of everything that keeps us from utter freedom in our response to God's gracious invitation to joy and sanctity. "If your right hand causes you sin, cut it off and throw it away." (Matthew 5:30)