Jabir reported the Apostle of Allaah ﷺ as saying “War is deception.”  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ الْحَرْبُ خُدْعَةٌ  

When the Prophet ﷺ intended to go on an expedition, he always pretended to be going somewhere else, and he would say: War is deception. Abu Dawud said: Only Ma'mar has transmitted this tradition. By this he refers to his statement "War is deception" through this chain of narrators. He narrated it from the tradition of 'Amr b. Dinar from Jabir, and from the tradition of Ma'mar from Hammam b. Munabbih on the authority of Abu Hurairah.  

أَنَّ النَّبِيَّ ﷺ كَانَ إِذَا أَرَادَ غَزْوَةً وَرَّى غَيْرَهَا وَكَانَ يَقُولُ الْحَرْبُ خُدْعَةٌ