What is the ruling on saying: "No, by God" if the heart and tongue are in agreement regarding the oath, and does it necessitate expiation?

Whoever says "No, by Allah" while swearing, then his oath is either a laghw (unintended, vain) oath if uttered spontaneously without intent, or an in'iqad (binding) oath if his tongue aligned with his heart. There is no expiation for a laghw oath. As for a binding oath, if the swearer was truthful in it, there is no expiation upon him.