Sayyiduna Adi bin Hatim (may Allah be pleased with him) said: A man delivered a speech in the presence of the Prophet (peace and blessings be upon him) and said: "Whoever obeys Allah and His Messenger is rightly guided, and whoever disobeys them both has gone astray." The Prophet (peace and blessings be upon him) said: "Be quiet, what a bad speaker you are!" He (peace and blessings be upon him) disliked his saying "whoever disobeys them both" (that is, combining Allah and the Messenger in a single pronoun).
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14307