In this case, I would argue that the difference lies in the individuals and in their contexts. Zechariah has a far greater grasp of God’s history with Man than Abraham does; Zechariah has access to the entire history of God’s interactions with the Israelites, but Abraham does not. Given the history of God’s interactions with his people, Zechariah should already know that God does miraculous things for our benefit; Abraham doesn’t have this kind of history or knowledge. I would argue that the way you treat a 5-year-old is a lot different than the way you treat an 18-year-old, when they say something contrary to fact…
In 1 Samuel 1 Hannah is immediately obedient to god whereas Mary expresses doubt.
Hmm… I’m not sure to what you’re referring. Does Hannah speak with an angel? Does Hannah receive a revelation from God? In what way is Hannah “immediately obedient to God”?
Because thier responses are so similiar “How can this be?” vs. “How shall I know this?”,
That’s just it: they’re not similar. Zechariah says, “by what will I know this?” – that is, he’s asking for a sign from Gabriel through which Gabriel might prove himself to Zechariah. In other words, Zechariah is asking for a sign from Gabriel! And, of course, Zechariah gets the sign he’s asking for – Gabriel strikes him temporarily mute!
Mary, on the other hand, asks a simple question: she’s been told that she will conceive in her womb, but – knowing that she is (and will be) a virgin, she doesn’t understand the mechanism by which she’ll become pregnant (hey – she’s a virgin, but she’s no dummy ;)). She asks ‘Πῶς ἔσται τοῦτο?’ – that is, “by what means will this happen?” … that is, she doesn’t laugh at Gabriel; she doesn’t ask him to prove that what he’s saying is true; she doesn’t doubt him. Rather, she simply asks for information… and Gabriel gives her that information.