Religious zeal can sometimes give certain people a very inflated opinion of themselves. They may look upon themselves as morally and spiritually superior to others.
Paul gives good advice: we are servants of Christ, and stewards of the mysteries. We apply them to our lives and pass them on. The judgement of others is not our job, nor are we competent to do it correctly.
Leave judgement to the Lord, and concentrate on being a servant. This is good advice. Our age has far too much religious belligerency and intolerance. It is not for us to decide who is a good Christian and who is not, nor are we anointed to designate who is pleasing to God and who is not. We are servants, not masters.
The disciples tried to understand the teachings of Jesus with an old way of religious thinking. Using the symbol of wineskins, Jesus said that it is not wise to pour new wine into old, tattered wineskins. They will burst, and good wine will be wasted. New wineskins are needed - and this symbolises new ways of thinking and new understandings. Being rigid, dogmatic, or resistant to change deadens the heart, mind, and soul. Being open to challenges and willing to have one's mind stretched is the first step on the road to spiritual enlightenment. Life is our classroom, and the Lord is our Teacher, so let us learn well.
Lord, open my heart and mind.