Whenever Messenger of Allah 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 Messenger of Allah 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.
سَمِعْتُ كَعْبَ بْنَ مَالِكٍ ؓ يَقُولُ كَانَ رَسُولُ اللَّهِ ﷺ قَلَّمَا يُرِيدُ غَزْوَةً يَغْزُوهَا إِلاَّ وَرَّى بِغَيْرِهَا حَتَّى كَانَتْ غَزْوَةُ تَبُوكَ فَغَزَاهَا رَسُولُ اللَّهِ ﷺ فِي حَرٍّ شَدِيدٍ وَاسْتَقْبَلَ سَفَرًا بَعِيدًا وَمَفَازًا وَاسْتَقْبَلَ غَزْوَ عَدُوٍّ كَثِيرٍ فَجَلَّى لِلْمُسْلِمِينَ أَمْرَهُمْ لِيَتَأَهَّبُوا أُهْبَةَ عَدُوِّهِمْ وَأَخْبَرَهُمْ بِوَجْهِهِ الَّذِي يُرِيدُ