Imam Ahmad said: Yasar told us on the authority of Hafs who said,
“Thabit told us that prophet Dawud (peace be upon him) divided the hours of the day and night among his family, so that not a single hour from the day or the night passed except that a member from the family of Dawud was standing in prayer. “
Allah swt said:
اعْمَلُوا آلَ دَاوُودَ شُكْرًا ۚ وَقَلِيلٌ مِّنْ عِبَادِيَ الشَّكُورُ
“Work, O family of David, in gratitude.” And few of My servants are grateful.
Dawud said, “O Lord! How can I thank you when thanks itself is a blessing from You” He swt said: “Now you have truly given thanks to Me, for you have realized that it is a blessing from Me.”
Source: Uddatul Sabireen by Imam ibnul Qayyim