JW Wall responds to David Plotz's book:

Those Biblical figures called heroes, and pillars, and faithful, and righteous: they doubted. They struggled. Faith did not preclude that; those titles that they earned could they have earned them without doubting? Would Abraham have been Abraham had he not negotiated for Sodom and Gomorrah? Moses, lost in the desert, doubted and struck the rock in his own name when bringing forth water.

There is an argument to be made that the struggle with doubt is among the most important aspects of faith... We oughtn’t confuse faith with mere belief the one is a component, an aspect of the other, though integral to it.

John Schwenkler adds his own two cents:

One reason why this sort of recognition is so important is that without it, the state of doubt can seem to be such a lonely – and, hence, sinful and shameful and unutterable – state to be in; with this recognition in place, however, doubt can be the sort of thing that we can bear and live through and – to use JL’s helpful phrase – struggle with together. To be clear: the point here is not that doubt is something to be celebrated or even simply taken for granted; the struggle is necessary, lest a doubting faith should give way to an outright unbelief. But the recognition that Moses and Abraham – and, for that matter, Mother Teresa and Pope Benedict and so on – are sharers in this struggle can, while perhaps not making the burden any lighter in itself, still make it that much easier to open oneself to the support of those others who, though faithful, are themselves quietly familiar with what the struggle with doubt entails.