Al-Aswad bin Qays relates that Sayyiduna Jundub (may Allah be pleased with him) said: A stone struck the foot of the Prophet (peace and blessings be upon him), and it was wounded and bled. So he (peace and blessings be upon him) said: "You are but a finger that has bled, and in the way of Allah is whatever has befallen you."
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 1694