‘And Joseph came in to them in the morning and saw them, and behold, they were sad. And he asked Pharaoh's officers who were in custody with him in his master's house, “Why are you looking so sad today?” '
When Joseph saw them it was clear to him that something was wrong. And he recognised that it was his responsibility to cheer them up. So he asked them what it was.
We note in the narrative the constant reminders that all this was taking place in prison. These accounts would be read out and it was necessary to keep in the hearer's mind the solemnity of the situation. It may also be that the writer is trying to bring home to us emphatically what Joseph's position was.
‘And they said to him, “We have dreamed a dream, and there is no one who can interpret it.” '
Their reply demonstrates the confidence they had built up in Joseph. They felt he was important enough and friendly enough to discuss the matter with (you do not tell such important things to just anyone). Thus they explained that they had had dreams which appeared to be important but that they had no means of obtaining their interpretation. They were no doubt filled with a sense of foreboding. Such portents were often a warning.
‘And Joseph said to them, “Do not interpretations belong to God? Tell it to me please.'
To speak of Yahweh would have been meaningless to the men. Thus Joseph speaks of God. Let them tell him the dreams and the implication is that his God will help him to interpret them.