Sayyiduna Salamah bin al-Akwa' (may Allah be pleased with him) narrates: The battle cry of the Prophet (peace and blessings be upon him) was: "Amit, amit (Kill, kill)!"
Imam al-Tabarani (may Allah have mercy on him) says: Ali bin Hakim added "in some of his military expeditions" in his narration.
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6244
Sayyiduna Salamah bin al-Akwa' (may Allah be pleased with him) narrates: A spy of the polytheists came to the Messenger of Allah (peace and blessings be upon him) while he (peace and blessings be upon him) was on a journey. He sat talking with the Companions, then slipped away. The Messenger of Allah (peace and blessings be upon him) said: "Search for him and kill him." I reached him before the others and killed him, and took his belongings, and he (peace and blessings be upon him) gave those belongings to me.
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6245
Sayyiduna Salamah bin al-Akwa' (may Allah be pleased with him) narrates: I was with the Prophet (peace and blessings be upon him) when a man came and entered the mosque. He (peace and blessings be upon him) said: "Catch him, for he is a spy." So I caught up with him, and since I was swift, I killed him, and the Prophet (peace and blessings be upon him) gave me his belongings.
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6246