"None should fast one or two days ahead of the month except, someone who had a prior habit for fasting, in which case let him fast." ' (Using translation from Nasāʾī 2173)   

أَنَّ رَسُولَ اللهِ ﷺ قَالَ «لَا يَتَقَدَّمَنَّ أَحَدٌ الشَّهْرَ بِيَوْمٍ وَلَا بِيَوْمَيْنِ إِلَّا أَحَدًا كَانَ يَصُومُ صِيَامًا فَلْيَصُمْهُ»  

"The messenger of Allah said: 'Do not fast one or two days ahead of the month, unless that happens to be a day that one of you habitually fasts."' Abu 'Abdur-Rahman (An-Nasai) said: This is a mistake. ' (Using translation from Nasāʾī 2174)   

قَالَ رَسُولُ اللهِ ﷺ «لَا تَتَقَدَّمُوا الشَّهْرَ بِصِيَامِ يَوْمٍ وَلَا يَوْمَيْنِ إِلَّا أَنْ يُوَافِقَ ذَلِكَ يَوْمًا كَانَ يَصُومُهُ أَحَدُكُمْ»