In the chapter of The Lord entitled "Belief in Christ, Imitation of Christ," Romano Guardini warns of the dangers of complacency in faith:

Woe to me if I say: "I believe" and feel safe in that belief. For then I am already in danger of losing it (see Cor 10:12). Woe to me if I say: "I am a Christian"--possibly with a side-glance at others who in my opinion are not, or at an age that is not, or that a cultural tendency flowing in the opposite direction. Then my so-called Christianity threatens to become nothing but a religious form of self-affirmation. I "am" not a Christian: I am on the way to becoming one--if God will give me the strength. Christianity is nothing one can "have;" nor is it a platform from which to judge others. It is a movement. I can become a Christian only as long as I am conscious of the possibility of falling away. The gravest danger is not a failure of the will to accomplish certain things; with God's help, I can always pull myself together and begin again. The real danger is that of becoming myself unchristian, and it is greatest when my will is most sure of itself. I have absolutely no guarantee that I shall be privileged to remain a follower of Christ, save in the matter of beginning, of being en route, of becoming, trusting, hoping and praying.