We have already discussed this in separate article and gave sufficient proof that in sunni books it’s well and authenticly established that prophet (sallalahu alaihi wa ala alihi wa sallam) use to pray while his right hand was on his left.
But I have seen some shia ignorant arguing with athar from Mujahid.
laith narrated from mujtahid that he considered keeping right hand on left hand, even if it is wrist or above that; he said it is what people of book (jews and christians) did
This is suppose to be quoted from Musannaf of ibn Abi Sheiba. Here arabic text of this athar:
حَدَّثَنَا أَبُو مُعَاوِيَةَ حَدَّثَنَا حَفْصٌ ، عَنْ لَيْثٍ ، عَنْ مُجَاهِدٍ ، أَنَّهُ كَانَ يَكْرَهُ أَنْ يَضَعَ الْيُمْنَى عَلَى الشِّمَالِ يَقُولُ عَلَى كَفِّهِ أَوْ عَلَى الرُّسْغِ وَيَقُولُ فَوْقَ ذَلِكَ وَيَقُولُ أَهْلُ الْكِتَابِ يَفْعَلُونَهُ
Narrated to me Abu Moawiyah – narrated to me Hafs -from Layth – from Mujahid, that he use to dislike puting right (hand) on the left, he says: on the wrist or hand, and says: higher than that, and says: Ahlalkitab do that.
First of all honestly it’s not quiet clear for me to which part of this hadith refer words regarding ahlalkitab. To all mentioned, or only to words “higher than that”.
Second, this athar is weak till Mujahid.
Layth that is ibn Abi Sulaim. Nasai and Yahya said he was weak. Ibn Hibban said he confused in the end of his life. (“Mizanul itidal” 3/420)
Hafs ibn Ghayth was thiqat, but as said some scholars he erred a lot in transmission of ahadeth.
Shia also cited second hadith from Wakiyah – Yusuf ibn Maymun – al-Hasan (al-Basri) that prophet (sallalahu alaihi wa ala alihi wa sallam) said: “As if I am looking now to reports of banu Israeil, they use to put their right hands upon their left hands in their prayers”.
First of all this reports is extremely weak. Because it’s disconnected and this is mursal of Hasan. His maraseel are most weak among maraseel.
Second, report isn’t authentic even till Hasan. Next after him is Yusuf ibn Maymun. Ahmad said he was nothing. Abu Hatim said he wasn’t strong, his ahadeth extremely rejected, weak. Bukhari said his ahadeth were extremely rejected. Nasai said he wasn’t truthful. Daraqutni said he was weak. (“Tahzib al-Kamal” 32/#7161)