According to Abu Hurairah, Muhammad said:

    There will be an Ayah (sign) in (the month of) Ramadan. Then, there will 'isabah (splitting into groups) in Shawwal. Then, there will be fighting in (the month of) Dhu al-Qi'dah. Then, the pilgrim will be robbed in (the month of) Dhu al-Hijjah. Then, the prohibitions will be violated in (the month of) al-Muharram. Then, there will be sound in (the month of) Safar, then the tribes will conflict with each other in the two months of Rabi' al-awwal & Rabi' al-thani. Then, the most amazing thing will happen between (the months of) Jumada and Rajab. Then, a well-fed she-camel will be better than a fortress (castle) sheltering a thousand (people).