Volume 4, Book 52, Number 293 :
Narrated by Hudhaifa (radiallaahu `anhu)
The Prophet (sallallaahu `alayhi wasallam) said (to us), ” List the names of those people who have announced that they are Muslims.” So, we listed one thousand and five hundred men. Then we wondered, “Should we be afraid (of infidels) although we are one thousand and five hundred in number?” No doubt, we witnessed ourselves being afflicted with such bad trials that one would have to offer the prayer alone in fear.
This count was done for either Uhud or before digging the Trench or at Hudaibiyah, according to the commentary. It was just a reassurance for Muslims and a confidence booster. Ultimately, all help is from Allah, as was proved in Badr, but having that advantage of number certainly helps.
Volume 4, Book 52, Number 294 :
Narrated by Al-A`mash (radiallaahu `anhu)
“We (listed the Muslims and) found them five hundred.” And Abu Muawiya (radiallaahu `anhu) said, “Between six-hundred to seven-hundred.”
Volume 4, Book 52, Number 81 :
Narrated by Anas bin Malik (radiallaahu `anhu)
In the life-time of the Prophet (sallallaahu `alayhi wasallam), Abu Talha (radiallaahu `anhu) did not fast because of the Jihad, but after the Prophet (sallallaahu `alayhi wasallam) died I never saw him without fasting except on ‘Id-ul-Fitr and ‘Id-ul-Adha.
Prophet (sallallaahu `alayhi wasallam) used to encourage his men to keep up their strength instead of fasting (voluntarily):
تقووا لعدوكم بالإفطار
Volume 1, Book 5, Number 268:
Anas bin Malik said, “The Prophet used to visit all his wives in a round, during the day and night and they were eleven in number.” I asked Anas, “Had the Prophet the strength for it?” Anas replied, “We used to say that the Prophet was given the strength of thirty (men).” And Sa’id said on the authority of Qatada that Anas had told him about nine wives only (not eleven).
He was definitely not an ordinary man, because he could do justice among all his wives.