It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Any man whose face becomes covered with dust in the path of Allah, Allah will keep him safe from the smoke of Hell on the Day of Resurrection; and any man whose feet become covered with dust in the path of Allah, Allah will keep his feet safe from Hell on the Day of Resurrection."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7451