Does one's deed become invalidated by saying about Allah that which one does not know, even if one intends to hope for acceptance from Allah and not to assert it definitively?

It is not permissible to definitively state that Allah does not accept the obedience of a specific person, because the acceptance or rejection of obedience is part of the Unseen, which only Allah knows. It is also incorrect to say that such a statement discourages good deeds, for the discouragement of deeds is also part of the knowledge of the Unseen. What the Sunnah has specified as deeds that invalidate good actions cannot be applied to a specific individual.