Unlike any other creature in the Universe, man is free in this world. God has not placed any curbs on him. But this freedom is for the purpose of putting man to the test, and is not meant to encourage him to lead a life of permissiveness, like the animals and then just pass away one day. Rather its purpose is that man should lead a morally upright life of his own free will, thus demonstrating that he is of the highest moral character.
One who conducts himself in this matter should be reckoned as God's special servant who, without any apparent compulsion, chose to be a man of principle; who, without being subjected to any external force, did of his own free will, what his Lord would have desired. This liberty accorded to man gives him the opportunity to gain credit for being the most superior of all God's creatures.
All the things in this world are God's subjects. The stars and satellites rotate in space entirely at their Lord's bidding. Trees, rivers, mountains, and all other such natural phenomena function according to the unchangeable ways of God laid down by Him in advance. Similarly, the animals follow exactly those instincts instilled in their species as a matter of Divine Will.