مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 2038
Fasting
Voluntary Fasting - Section 1
وَعَنْ عِمْرَانَ بْنِ حُصَيْنٍ عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: أَنَّهُ سَأَلَهُ أَوْ سَأَلَ رَجُلًا وَعِمْرَانَ يَسْمَعُ فَقَالَ: «يَا أَبَا فُلَانٍ أَمَا صُمْتَ مِنْ سَرَرِ شَعْبَانَ؟» قَالَ: لَا قَالَ: «فَإِذَا أَفْطَرْتَ فَصُمْ يَوْمَيْنِ»
‘Imran b. Husain said that the Prophet (ﷺ) asked him, or that he asked a man in ‘Imran’s hearing, “Father of so and so, did you not fast the last day of Sha'ban?" When, he replied that he had not, he said, “If you did not observe a fast, you must fast for two days."* *To reconcile this tradition with that of Abu Huraira at the foot of p.420 it is suggested that the man had made a vow to observe this fast, or that it was his custom. (Bukhari and Muslim.)
Mishkat al-Masabih, 2038مُتَّفَقٌ عَلَيْهِ (الألباني)