I will say that there is a difference between a question and a doubt.
A question is the mind searching to understand the faith, but does not question the truth of it.
A doubt is the mind questioning whether the article of faith is true until understood.
“Nor do I seek to understand that I may believe, but I believe that I may understand.
For this too I believe, that unless I first believe, I shall not understand.”
St. Anselm of Canterbury
From Saint Augustine: “Understanding is the reward given by faith. Do not try to understand in order to believe, but believe in order to understand.”
For example, to speculate, “I wonder if Jesus is really present in Eucharist,” is to question the
truthfullness of Jesus and deny his authority. But to say, “I wonder just how Jesus is really
present in the Eucharist,” is a question to understand “how” after the fact of belief.
On the other hand the devil may present someone with the thought, “You really don’t believe
that He could possibly be present because that would certainly be below His dignity.”
Now the person has to decide. Do I reaffirm my belief or do I doubt and hesitate and
begin to wonder. The person must respond, “I believe Lord, help my unbelief.” He cannot
say, “well I need more time to consider this,” or “I’m not so sure, I should be careful,
there are others who don’t think this.”
And also the true faith must be complete. It would be foolish to suppose that we can pick
and choose among the things God has told us according to our particular taste. For example
to say “I believe in being saved, but not in Baptism,” is to say that “God can be wrong.”
And from this follows “can we believe in God at all.”