Evangelii Gaudium §85

85. One of the more serious temptations which stifles boldness and zeal is a defeatism which turns us into querulous and disillusioned pessimists, “sourpusses”. Nobody can go off to battle unless he is fully convinced of victory beforehand. If we start without confidence, we have already lost half the battle and we bury our talents. While painfully aware of our own frailties, we have to march on without giving in, keeping in mind what the Lord said to Saint Paul: “My grace is sufficient for you, for my power is made perfect in weakness” (2 Cor 12:9). Christian triumph is always a cross, yet a cross which is at the same time a victorious banner borne with aggressive tenderness against the assaults of evil. The evil spirit of defeatism is brother to the temptation to separate, before its time, the wheat from the weeds; it is the fruit of an anxious and self-centred lack of trust.