Sayyiduna Salman al-Farisi (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "Whoever stands guard in the path of Allah for a day and a night receives the reward of a month of fasting and standing (in prayer). And if someone dies while standing guard, this reward of his continues, his provision continues to be granted, and he is kept safe from trials."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 17885