Mishkat al-Masabih
Jarhad reported the Prophet (ﷺ) as saying, "Do you not know that the thigh is a private part?” Tirmidhi and Abu Dawud transmitted it.
وَعَنْ جَرْهَدٍ: أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «أَمَا عَلِمْتَ أَنَّ الْفَخِذَ عَوْرَةٌ» . رَوَاهُ التِّرْمِذِيّ وَأَبُو دَاوُد
Reference