Reliability of Hadeeths?

Praise be to Allah

Among the ahadeeth
which are attributed to the Prophet (peace and blessings of Allah be upon
him), there are some which are saheeh (sound), concerning which there is no
doubt that they are the words of the Prophet (peace and blessings of Allah
be upon him). There are others which are da’eef (weak) and there are doubts
that they can be attributed to him. Both saheeh and da’eef are well known to
the scholars. Books of saheeh have been compiled which include saheeh
ahadeeth such as Saheeh al-Bukhari and Saheeh Muslim; there are other books
which include saheeh ahadeeth and others, like the other books of hadeeth,
The scholars have gone to great lengths to distinguish the saheeh from
others, as is well known to young students let alone those who have
specialized in the study of the Sunnah.