Hadithcore
Mishkat al-Masabih, 2257

Ibn ‘Umar used to say, “Your raising of your hands is an innovation. God’s messenger did no more than this,” meaning that he raised them to his breast. Ahmad transmitted it.

وَعَنِ ابْنِ عُمَرَ أَنَّهُ يَقُولُ: إِنَّ رَفْعَكُمْ أَيْدِيَكُمْ بِدْعَةٌ مَا زَادَ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَلَى هَذَا يَعْنِي إِلَى الصَّدْر رَوَاهُ أَحْمد

References1 variant
In-Book Reference
Book 9, Hadith 32