Bukhari

Narrated `Abdullah bin `Amr: The news of my fasting was mentioned to the Prophet . So he entered upon me and I put for him a leather cushion stuffed with palm-fibres. The Prophet sat on the floor and the cushion was between me and him. He said to me, "Isn't it sufficient for you (that you fast) three days a month?" I said, "O Allah's Apostle! (I can fast more than this)." He said, "You may fast) five days a month." I said, "O Allah's Apostle! (I can fast more than this)." He said, "(You may fast) seven days." I said, "O Allah's Apostle!" He said, "Nine." I said, "O Allah's Apostle!" He said, "Eleven." I said, "O Allah's Apostle!" He said, "No fasting is superior to the fasting of (the Prophet David) which was one half of a year, and he used, to fast on alternate days. (See Hadith No. 300, Vol 3)

Narrated Ibrahim: 'Alaqama went to Sham and came to the mosque and offered a two-rak`at prayer, and invoked Allah: "O Allah! Bless me with a (pious) good companion." So he sat beside Abu Ad-Darda' who asked, "From where are you?" He said, "From the people of Kufa." Abu Darda' said, "Wasn't there among you the person who keeps the secrets (of the Prophet ) which nobody knew except him (i.e., Hudhaifa (bin Al-Yaman)). And isn't there among you the person whom Allah gave refuge from Satan through the request (tongue) of Allah's Apostle? (i.e., `Ammar). Isn't there among you the one who used to carry the Siwak and the cushion (or pillows (of the Prophets)? (i.e., Ibn Mas`ud). How did Ibn Mas`ud use to recite 'By the night as it conceals (the light)?" (Sura 92). 'Alqama said, "Wadhdhakari Wal Untha' (And by male and female.") Abu Ad-Darda added. 'These people continued to argue with me regarding it till they were about to cause me to have doubts although I heard it from Allah's Apostle."