Hadithcore
Mishkat al-Masabih, 3230

‘A’isha told that when Sauda became old she said, “Messenger of God, I appoint to ‘A'isha the day you visit me” (Cf. the last tradition in this chapter). So God’s Messenger allotted two days to ‘A’isha, hers and Sauda’s. (Bukhari and Muslim.)

وَعَنْ عَائِشَةَ أَنَّ سَوْدَةَ لَمَّا كَبِرَتْ قَالَتْ: يَا رَسُولَ اللَّهِ قَدْ جَعَلْتُ يَوْمِي مِنْكَ لِعَائِشَةَ فَكَانَ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يُقَسَّمُ لِعَائِشَةَ يَوْمَيْنِ يَوْمَهَا وَيَوْم سَوْدَة

References1 variant
In-Book Reference
Book 13, Hadith 148