they question me on things I know nothing about.
12 They repay me evil for good
and leave me like one bereaved.
13 Yet when they were ill, I put on sackcloth
and humbled myself with fasting.
When my prayers returned to me unanswered,
14 I went about mourning
as though for my friend or brother.
I bowed my head in grief
as though weeping for my mother.
It is important to remember that the Judaeo-Christian view is that we are embodied beings, not spirits inhabiting a body like a driver in a car. Therefore what we do with our bodiliness affects our spirit. McKnight's book (as is the work of Dallas Willard) is very good in bringing out the importance of this for prayer-fasting.