Many are the afflictions of the righteous,
but He will deliver them from them all.
The Lord shall guard all their bones;
not one of them shall be broken.
(Psalm 33:20-21)

Brethren, let us not receive this carnally.
Bones are the firm supports of the faithful.
For as in flesh our bones give firmness, so in the heart of a Christian it is faith that gives firmness.
The patience then which is in faith, is as the bones of the inner man:
this is that which cannot be broken…
[So He speaks of those] bones which we call the firm supports of faith,
that is, patience and endurance in all tribulations.
These are the bones which are not broken.
St. Augustine