" أَلاَ لاَ تَقَدَّمُوا الشَّهْرَ بِيَوْمٍ أَوِ اثْنَيْنِ إِلاَّ رَجُلٌ كَانَ يَصُومُ صِيَامًا فَلْيَصُمْهُ "
It was narrated from Abu Hurairah that the Messenger of Allah used to say: "Do not fast one or two days ahead of the month, unless the one who used to observe a regular fast. In that case let him fast." '