Sunan an-Nasa'i, Book 22, Hadith 291 (In-Book) ⓘ

It was narrated from Mutarrif bin 'Abdullah bin 'Abdullah bin Ash-Shikhkhir: "My father told me that he heard the Messenger of Allah say, when mention was made in his presence of a man who fasted for the rest of his life: 'He neither fasted nor broke his fast."' 'Ata said: "someone who heard him told me that Ibn 'Umar (said) that the Prophet said: 'Whoever fasts every day of his life, then he has not fasted."

أَخْبَرَنِي عَمْرُو بْنُ هِشَامٍ، قَالَ حَدَّثَنَا مَخْلَدٌ، عَنِ الأَوْزَاعِيِّ، عَنْ قَتَادَةَ، عَنْ مُطَرِّفِ بْنِ عَبْدِ اللَّهِ بْنِ الشِّخِّيرِ، أَخْبَرَنِي أَبِي أَنَّهُ، سَمِعَ رَسُولَ اللَّهِ صلى الله عليه وسلم وَذُكِرَ عِنْدَهُ رَجُلٌ يَصُومُ الدَّهْرَ قَالَ ‏ "‏ لاَ صَامَ وَلاَ أَفْطَرَ ‏" ‏ ‏.‏