On the contrary, it is to show that a free person and one possessed by another are not equal in the authority that they have over things that they apparently possess. A free person may spend of his possessions as, when and however he wishes, while a person, who himself is possessed does not have the authority to spend things, which may apparently seem to be in his possession. The referred parable is to show the stupidity in ascribing partners to God and then to consider these partners to have the power to bestow good things upon humans. The Qur an has stressed that everything besides the one God is, in fact, a creation and a possession of the One God. It is absolutely subservient to the commands and directives of God.
Nothing has any power to bestow anything upon humans.
Thus, those who ascribe partners to the One God and then call upon them to help them and to bestow upon them the good things of life, are like those whose hopes are attached with slaves and souls, which themselves are possessed by others. It is in this context that the Qur an has given the referred example. And they worship besides the One God things, which have absolutely no authority to bestow anything upon them, neither in the heavens nor the earth, and are absolutely powerless. Do not give examples about God. Indeed God knows, while you do not.