Our Lord scolds his apostles with this word when storm waves are threatening to swamp the boat in which they are crossing the lake: "Why are you afraid [deilos], O you of little faith" (Matthew 8:26)? The implication is clear: anyone who is timid and fearful in the face of a threat must be lacking in faith.
THE SPIRIT: PAUL'S ANTIDOTE TO FEAR
As so often happens, however, when scripture challenges us, it also shows us how to meet that challenge. I have found one passage in the Second Letter to Timothy to be particularly helpful: "For this reason I remind you to stir into flame the gift of God that you have through the imposition of my hands. For God did not give us a spirit of cowardice [deilia], but rather of power and love and self-control" (2 Tim 1:6-7). Here Paul is contrasting the spirit of cowardice with three qualities of the "spirit" that can help us respond more courageously to the challenges of the wilderness. Each of them -- power, love, and self-control -- is worth considering individually.
Think of something you are afraid of and consider how each of the three spirits mentioned in 2 Timothy might help you deal with that particular fear: (a) relying on God's power instead of your own. (b) loving concern for others, and (c) being rooted firmly in God.
“Afraid” [deilos] or “fear” [deilia] appear in Wisdom 9:14; Sirach 2:12; I Macc. 3:56.
"Do not be daunted immediately by fear and run away from the road that leads to salvation. It is bound to be narrow at the outset. But as we progress in this way of life and in faith, we shall run on the path of God's commandments, our hearts overflowing with the inexpressible delight of love."