Yahya related to me from Malik from Salama ibn Safwan ibn Salama az-Zuraqi that Zayd ibn Talha ibn Rukana, who attributed it to the Prophet, may Allah bless him and grant him peace, said, “The Messenger of Allah, may Allah bless him and grant him peace, said, ‘Every deen has an innate character. The character of Islam is modesty.’ ”
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ سَلَمَةَ بْنِ صَفْوَانَ بْنِ سَلَمَةَ الزُّرَقِيِّ، عَنْ زَيْدِ بْنِ طَلْحَةَ بْنِ رُكَانَةَ، يَرْفَعُهُ إِلَى النَّبِيِّ صلى الله عليه وسلم قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ “‏ لِكُلِّ دِينٍ خُلُقٌ وَخُلُقُ الإِسْلاَمِ الْحَيَاءُ ‏”‏ ‏.‏
Sunnah.com reference : Book 47, Hadith 9
USC-MSA web (English) reference : Book 47, Hadith 9
Arabic reference : Book 47, Hadith 1644