The Prophet (may Allah's peace and blessings be upon him) was told that ‘Abdullāh ibn ‘Amr swore to fast every day and stay in prayer all night without sleep for his entire life. So he asked him whether he had said that and he answered that he had. The Prophet told him that such a commitment would be beyond his endurance, so he should combine worship with rest by fasting and eating; praying at night and sleeping and restricting his voluntary fasting to three days a month, which would grant him the reward of fasting the whole year. However, ‘Abdullāh said that he could handle more than that. He kept asking to do more fasting until he reached its ultimate form, which is fasting like Prophet Dawūd, namely fasting every other day. He asked to do more from a desire to do more good deeds, but the Prophet (may Allah's peace and blessings be upon him) told him that there was no fast better than that.