My understanding of Hadith is that it is not a separate source of Islam. Subject matter of every Hadith must originate in the Holy Qur'an or the Sunnah. I say this because our Prophet (sws) could never do or say anything regarding Islam that was not part of the two basic sources (the Holy Qur'an and the Sunnah). Therefore, a Hadith which cannot be reconciled with any of these two sources should be rejected. Is this approach correct?
Hadith is the record of the life history, sayings and deeds of the Prophet (sws). Only those of its contents, which are religious in nature or have to do with morality, should be gauged on the yardstick of the Holy Qur'an and the Sunnah. It is right to say that the Prophet (sws) could not do anything contrary to the Holy Qur'an and the Sunnah but one cannot claim that all that is recorded as the acts and sayings of the Prophet (sws) need to be related to the Holy Qur'an or the Sunnah. The Prophet (sws) was a human being who lived in a particular culture during a particular period of history. He had his personal tastes, likes and dislikes for things as all normal humans have. Therefore, he must have said or done things which have nothing to do with religion. I do not think it would be necessary to establish a relation of his saying, for example that his favorite color was white, with religion. Likewise, there must be a whole lot of other things which do not relate to religion.