«أفضل الصوم صوم أخي داود كان يصوم يوما ويفطر يوما ولا يفر إذا لاقى»
The Prophet (peace and blessings be upon him) said:
"The most excellent fasting is the fasting of my brother Dawud (peace be upon him). He used to fast one day and break his fast the next (that is, not fast), and when he faced the enemy on the battlefield, he would not turn his back."
Hadith Referenceصحیح الجامع الصغیر / حرف الألف / 1120