It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that Khawla bint Yasar (may Allah be pleased with her) once came to the service of the Prophet (peace and blessings be upon him) and said, "O Messenger of Allah! I have only one garment and during my days of impurity, I also wear it." The Prophet (peace and blessings be upon him) said, "When you become pure, wash the place where the blood has stained, and then pray in it." She said, "O Messenger of Allah! What if the mark of the blood stain does not go away?" He said, "Water is sufficient; it does not matter if the mark does not disappear."