How authentic are books such as Mishkat or Muwatta with respect to Sahih al-Bukhari or Sahih Al-Muslim?
In my opinion, the authenticity of the Mishkaat al-Masaabeeh and the Muwatta of Imam Malik, should not compared to that of the Sahih al-Bukhari or the Sahih Muslim.
As far as the Mishkaat is concerned, it is not an original compilation of narratives ascribed to the Prophet (pbuh), as are the other three referred books. All the other referred books are the original compilations narratives ascribed to the Prophet (pbuh), while Mishkaat is a secondary compilation of these narratives, based upon the original compilations, including Muwatta, Sahih al-Bukhari, Sahih Muslim and a number of others.
As far as the Muwatta of Imam Malik is concerned, even though it is one of the most respected and, by some, considered to be a highly reliable source of narratives ascribed to the Prophet (pbuh), yet because of the mere fact that it was compiled before the standardization and stipulation of elaborate principles of accepting narratives to be correct, some of its narratives may not come up to the standards, which were later set by the Muhadditheen. Sahih al-Bukhari and Sahih Muslim were both compiled after the standardization and stipulation of the detailed principles of accepting narratives ascribed to the Prophet (pbuh) as accurate. These books were, thus, prepared in compliance with these standardized principles.
I hope this helps.
September 11, 2001