It is narrated from Sayyiduna Ibn Amr (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "The most beloved way of fasting is that of Sayyiduna Dawud (peace be upon him); he would fast one day and leave it the next day, and he would not flee when facing the enemy. He also said: 'The one who fasts continuously has not truly fasted.'"