They complained to the Messenger of Allah ﷺ about the intrusive whispers they were experiencing and said, "Messenger of Allah, we find within ourselves thoughts so terrible that any one of us would rather fall from the sky than speak them aloud."The Prophet ﷺ replied, "That is pure faith."
حدثنا مؤمل حدثنا حماد عن ثابت عن شهر بن حوشب عن خاله
شكوا إلى رسول الله ﷺ ما يجدون من الوسوسة وقالوا يا رسول الله إنا لنجد شيئا لو أن أحدنا خر من السماء كان أحب إليه من أن يتكلم به فقال النبي ﷺ ذاك محض الإيمان
No references are available.
Its isnad is hasan, because of Shahr bin Hawshab, and the hadith was narrated by Muslim 1/119, no. 132, in Iman, and by Bukhari in Adab al-Mufrad, no. 1285.