This theory runs into many philosophical predicaments. One argument is that it entails that morality is subjective. If divine command theory has truth in it, morality is based simply on god's impulse. Therefore, if god had willed spite and deceitfulness to be merits, and compassion and donation to be vices, then they would have been such. The natural response to this argument is that god would not have demanded such things because he would not demand evil, but this reply entails a spherical explanation as it is only god's command that makes them evil.
In the field of medicine, it relates to the practice of mercy killing or euthanasia, as God does not command people to murder.