Yahya related to me from Abu'z-Zinad from al-Araj from Abu
Hurayra that the Messenger of Allah, may Allah bless him and grant him
peace, said, "A group of angels in the night and a group of angels in
the day alternate with each other among you, and gather together at
the time of the asr and fajr prayers. Then those that have spent the
night among you ascend, and He asks them, and He knows best, 'How did
you leave my slaves?' and they say, 'When we left them they were
praying, and when we came to them they were praying.' "
Muwatta Malik Book 9, Hadith 90
Yahya related to me from Malik that Humayd ibn Qays and Thawr ibn
Zayd adDili both informed him that the Messenger of Allah, may Allah
bless him and grant him peace, (and one of them gave more detail than
the other),saw a man standing in the sun. The Messenger asked, "What's
wrong with him?" The people said, "He has vowed not to speak or to
seek shade from the sun or to sit and to fast." The Messenger of
Allah, may Allah bless him and grant him peace, said, "Go and tell him
to speak, seek shade, and sit, but let him complete his fast."
Malik said, "I have not heard that the Messenger of Allah, may
Allah bless him and grant him peace, ordered the man in question to do
any kaffara. The Messenger of Allah, may Allah bless him and grant him
peace, only ordered him to complete that in which there was obedience
to Allah and to abandon that in which there was disobedience to
Allah."
Muwatta Malik Book 22, Hadith 7