God is the most obligated being that there is.  He is obligated by his own nature.  He is infinite in his wisdom; therefore he can never do anything that is unwise.  He is infinite in his justice; therefore he can never do anything that is unjust.  He is infinite in his goodness; therefore he can never do anything that is not good.  He is infinite in his truth; therefore it is impossible that he should lie.
J. Gresham Machen