It is narrated from Sayyiduna Abu al-Darda (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Sayyiduna Dawud (peace be upon him) used to make this supplication: 'Allahumma inni as'aluka hubbaka, wa hubba man yuhibbuka, wal-'amalal-ladhi yuballighuni hubbaka, Allahummaj'al hubbaka ahabba ilayya min nafsi wa ahli wa minal-ma'il-barid' (O Allah, I ask You for Your love, the love of those who love You, and the deeds that will bring me to Your love. O my Lord, make Your love dearer to me than my own self, my family and cold water)." And whenever the Prophet (peace and blessings be upon him) mentioned Sayyiduna Dawud (peace be upon him) or related something about him, he would say: "He was the most devoted in worship of all human beings." This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.