وَعَنِ ابْنِ مَسْعُودٍ كَانَ يَقُولُ: مِنَ السُّنَّةِ إِخْفَاءُ التَّشَهُّدِ. رَوَاهُ أَبُو دَاوُدَ وَالتِّرْمِذِيُّ وَقَالَ: هَذَا حَدِيثٌ حَسَنٌ غَرِيبٌ
Ibn Mas'ud used to say, “It pertains to the sunna to repeat the tashahhud quietly.” Abu Dawud and Tirmidhi transmitted it, and Tirmidhi said this is a hasan gharib tradition.
Source: Mishkat al-Masabih — repository translation · Al-Khatib Al-Tabrizi — authenticity/grade metadata requires independent source review · Sunnah.comAudio not available for the selected reciter.
Source: Mishkat al-Masabih — repository arabic · Al-Khatib Al-Tabrizi · Sunnah.com