Muhammed bin Abi Haatim (rahimahullah) mentions:
On one occasion, Imaam Bukhaari (rahimahullah) was invited to the orchard of one of his companions. Imaam Bukhaari (rahimahullah) accepted the invitation and proceeded to the orchard. Thereafter, while at the orchard, Imaam Bukhaari (rahimahullah) began to perform nafl salaah. After completing his nafl salaah, Imaam Bukhaari (rahimahullah) lifted the hem of his kurta and said to one of his companions, “See if there is anything inside my kurta.”
Upon close inspection, the person found that a wasp had entered the kurta of Imaam Bukhaari (rahimahullah) while he was performing salaah and had stung him sixteen or seventeen times, causing his body to become swollen.
Observing the painful injury, someone asked, “Why did you not hasten in completing your salaah when you were stung the first time?” Imaam Bukhaari (rahimahullah) replied, “I was engaged in reciting a surah, and I did not wish to end the salaah without completing it.”
(Siyar ‘Alaamin Nubalaa 12/442)