All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
The Hadeeth of Waa’il ibn Hujr regarding the description of the prayer has come with various wordings that indicate a single meaning related to the placement of one’s hands while standing which is putting the right hand on top of the left during the prayer. Following are the different wordings of this Hadeeth:
“…he then took his left with his right"…
“…he took hold, with his right, of his left"…
“…he placed his right hand upon the back of his left palm, wrist and forearm"…
“…he placed his right hand upon the left in the prayer near the wrist"…
“…he placed his right hand upon his left hand on his chest"…
This last version is that of Ibn Khuzaymah.
It is not reported through the Hadeeth of Waa’il that this was “under the navel” or “under his navel.” The narration of Ibn Abi Shaybah in his Musannaf does not contain “under the navel.” We could not find anyone of the scholars who attributed this addition to Ibn Abi Shaybah, so we do not know who are those "some people" whom the questioner indicated as attributing this to the Musannaf?
Indeed, placing the hands under the navel has come in a Hadeeth of ‘Ali with a weak chain of narrators. An-Nawawi said: "As for the Hadeeth of ‘Ali that he said: “From the Sunnah in the prayer is placing the hands upon the hands under the navel”, it is Dha‘eef (weak) and that (opinion) is agreed upon. Ad-Daaraqutni and Al-Bayhaqi reported it via Abu Shaybah ‘Abd-ur-Rahmaan ibn Is-haaq Al-Waasiti and he is Dha‘eef by consensus…"
Al-Haafith Ibn Hajar said in Ad-Diraayah: "Its Isnaad [chain of transmission] is Dha‘eef and is contradicted by the Hadeeth of Waa’il ibn Hujr who said: “I prayed with the Prophet, sallallaahu ‘alayhi wa sallam, and he placed his right hand upon his left hand on his chest.” as reported by Ibn Khuzaymah. Muslim also relayed it but without the phrase “on his chest."
Abu Daawood also narrated another Hadeeth but from Abu Waa’il – not Waa’il ibn Hujr – who said: Abu Hurayrah said: “The taking of hands upon hands in the prayer occurs under the navel.” Al-Albaani considered it Dha‘eef and Abu Daawood himself said that it was not strong.
In conclusion, the Hadeeth of Waa’il ibn Hujr does not contain “under the navel.”
For more benefit, please refer to Fataawa 82692 and 83175 regarding the Hadeeth of Waa’il ibn Hujr .
Allaah Knows best.