Abu Huraira reported: Some of the companions came to the Prophet, peace and blessings be upon him, and they asked him, “We find within ourselves that which is to grievous to speak of.” The Prophet said, “You have indeed found it so?” They said yes. The Prophet said, “That is pure faith.”
Source: Ṣaḥīḥ Muslim 132
Grade: Sahih (authentic) according to Muslim
عَنْ أَبِي هُرَيْرَةَ قَالَ جَاءَ نَاسٌ مِنْ أَصْحَابِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَسَأَلُوهُ إِنَّا نَجِدُ فِي أَنْفُسِنَا مَا يَتَعَاظَمُ أَحَدُنَا أَنْ يَتَكَلَّمَ بِهِ قَالَ وَقَدْ وَجَدْتُمُوهُ قَالُوا نَعَمْ قَالَ ذَاكَ صَرِيحُ الْإِيمَانِ
132 صحيح مسلم كتاب الإيمان باب بيان الوسوسة في الإيمان وما يقوله من وجدها