Sahih al-Bukhari 2948
صحيح البخاري#2948SahihNarrated Ka`b bin Malik:Whenever Allah's Messenger (ﷺ) intended to carry out a Ghazwa, he would use an equivocation to conceal his real destination till it was the Ghazwa of Tabuk which Allah's Messenger (ﷺ) carried out in very hot weather. As he was going to face a very long journey through a wasteland and was to meet and attack a large number of enemies. So, he made the situation clear to the Muslims so that they might prepare themselves accordingly and get ready to conquer their enemy. The Prophet (ﷺ) informed them of the destination he was heading for
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 56:160