Sure we must have an answer, but the answer Peter speaks to regards the "hope within you." It is that within element -- that spiritual formation of the character and attitude of Jesus -- which is at the heart of spiritual formation.
With the renewed interest in spiritual formation has also come a renewed interest in disciplines that assist in the formation of Christlikeness. Disciplines like fasting, meditation, accountability, etc. have become more valued.
It's interesting to see in the context of Matthew 6.1-18 Jesus speak of three disciplines of Christian faith: giving, praying and fasting. No one argues the necessity of the first two; giving and praying are integral components of every Lord's Day assembly of God's people. So why do we traditionally had such a hangup regarding the value of fasting?
"Where are the people today who will respond to the call of Christ? Have we become so accustomed to 'cheap grace' that we instinctively shy away from more demanding calls to obedience? 'Cheap grace is grace without discipleship; grace without the cross.' Why has the giving of money, for example, been unquestionably recognized as an element in Christian devotion and fasting so disputed? Certainly we have as much, if not more, evidence from the Bible for fasting as we have for giving. Perhaps in our affluent society, fasting involves a far larger sacrifice than the giving of money" (Richard Foster, Celebration of Discipline, p.54).
