Why do you classify the hadiths about placing the hands below the navel (in the prayer) as weak when the great Muhaddith (Hadith specialist) Is-haaq ibn Rahawayh classified them as authentic?

All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.

We do not classify a hadeeth as authentic or weak of our own accord; rather, we rely on trustworthy Imaams and their statements. If they differ in opinion, then we follow the view of the most knowledgeable amongst them or of the majority of them.

As for what you mentioned regarding Is-haaq ibn Raahawayh authenticating these ahaadeeth, then we have not come across this. Rather, we have come across the statement of An-Nawawi about the consensus that this hadeeth is weak: “Az-Zayla`i said in Nasb Ar-Raayah about this hadeeth, ‘It was reported by Ahmad in his Musnad, and by Ad-Daaraqutni and then by Al-Bayhaqi from Ahmad in their Sunan. Al-Bayhaqi said in Al-Ma`rifah, 'Its chain of narrators is not authentic. It was only reported by Abdur-Rahmaan ibn Is-haq Al-Waasiti, whose narrations are abandoned.'”

An-Nawawi said in Al-Khulaasah and in Sharh Muslim, “There is unanimous agreement about this hadeeth being weak, because Abdur-Rahman ibn Is-haaq is weak according to the consensus of the scholars.”

Allah knows best.