That's a strange quote. Is it really from Christian Theology?
'Can' here seems to mean 'will'. If nothing is refused at 3 o'clock (the strangeness I refer to), then you will obtain what you ask for.
Jesus actually didn't make appointment hours though. He just said, "Ask, believing, and it will be given [to] you" (paraphrase). I'm not sure who he was referring to (obviously someone else.)
PS: You need to start all your sentences with capital letters.
Student or Learner