'Possible' in the Bible

And he gave them teaching in the form of a story, saying, Is it possible for one blind man to be guide to another? will they not go falling together into a hole?

And he, from inside the house, would say in answer, Do not be a trouble to me; the door is now shut, and my children are with me in bed; it is not possible for me to get up and give to you?

But he said, Things which are not possible with man are possible with God.

David then gives him the name of Lord, so how is it possible for him to be his son?