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. (Using translation from Bukhārī 2948)
سَمِعْتُ كَعْبَ بْنَ مَالِكٍ يَقُولُ كَانَ رَسُولُ اللهِ ﷺ قَلَّمَا يُرِيدُ غَزْوَةً يَغْزُوهَا إِلَّا وَرَّى بِغَيْرِهَا حَتَّى كَانَ غَزْوَةُ تَبُوكَ فَغَزَاهَارَسُولُ اللهِ ﷺ فِي حَرٍّ شَدِيدٍ اسْتَقْبَلَ سَفَرًا بَعِيدًا وَمَفَازًا وَاسْتَقْبَلَ غَزْوَ عَدُوٍّ كَثِيرٍ فَجَلَا لِلْمُسْلِمِينَ أَمَرَهُمْ لِيَتَأَهَّبُوا أُهْبَةَ عَدُوِّهِمْ أَخْبَرَهُمْ بِوَجْهِهِ الَّذِي يُرِيدُ