It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "How many a fasting person gets nothing from his fast but hunger and thirst, and how many a person who stands in prayer at night gets nothing from his standing but sleeplessness."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13356