Jehovah is God and He specializes in making the impossible possible. When He comes, He announced His presence with unbelievable words.
In Luke 1, two people were confronted with impossible things: Zechariah the priest and Mary, the mother of Jesus. They asked two seemingly similar question, based on the reality of their circumstances; yet, they got different responses.
One said: “God shall I know this…” It sounded like “Why would you say that to me, especially now that my wife and I are old”. His response projected absolute disbelief and real disinterest in the prospect of having a child anymore (the probably had tried all their youthful days). The angel responded with his Resume; he had to reaffirm that he is from the LORD, just in case he did not know…
The other said: “How can this be…?” It sounded more like “How do you intend to do this since I am still a virgin”. Her response projected keen interest in what form it would take to do that (she knew God is able to do all things, especially in unbelievable ways like He parted the Red Sea, a story they had learnt of God). That response provoked an explanation from the same angel on how this it would happen…
Unbelief asks WHY? Faith asks HOW?
Unbelief received negative repercussions. Faith recieves news of other signs and wonders to affirm the word received.
It is impossible to walk with God without faith.