This is an unhappy expression, bringing in the name of God where it does not occur. In the O.T. it is chalilah, 'far be it.' Ge 44:7,17, etc. In the N.T. ?? ???????, 'let it not be.' Ro 3:4,6,31, etc.
And they said unto him, Why says my lord these words? God forbid that your servants should do according to this thing:
And he said, God forbid that I should do so: but the man in whose hand the cup is found, he shall be my servant; and as for you, get you up in peace unto your father.
God forbid: yea, let God be true, but every man a liar; as it is written, That you might be justified in your sayings, and might overcome when you are judged.
God forbid: for then how shall God judge the world?
Do we then make void the law through faith? God forbid: yea, we establish the law.