Sayyiduna Salman (may Allah be pleased with him) said: I heard the Messenger of Allah (peace and blessings be upon him) say: "Standing guard for a day and a night in the path of Allah is better than fasting a month and standing it in prayer. Whoever dies while standing guard, the deed he used to do continues for him, and he is kept safe from the trial."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6153