He said, "The Messenger of Allah ﷺ rarely intended to undertake a military expedition without disguising it as another, until the expedition of Tabuk. The Messenger of Allah ﷺ set out on this expedition in intense heat, facing a long journey through waterless wilderness, confronting a numerous enemy. So he made the matter clear to the Muslims so they could prepare adequately for their enemy, and he informed them of the destination he intended."
يقول: كان رسول الله ﷺ قلما يريد غزوة يغزوها إلا ورى بغيرها حتى كانت غزوة تبوك، فغزاها رسول الله ﷺ في حر شديد، واستقبل سفرا بعيدا ومفازا، واستقبل غزو عدو كثير، فجلى للمسلمين أمرهم ليتأهبوا أهبة عدوهم، وأخبرهم بوجهه الذي يريد.
Bukhari narrated it in the Book of Jihad and Expeditions (2948), and Muslim in the Book of Repentance (54:2769), both from the hadith of Zuhri, who said, "Abdul-Rahman bin Abdullah bin Kaab bin Malik informed me that Abdullah bin Kaab, who used to guide his father Kaab among his sons, said, 'I heard Kaab bin Malik,'" and he then related it.