Umm Salama reported that the Prophet, may Allah bless him and grant him peace, was in his house and called for a slave of his (or hers) and she was slow in coming. The anger showed in his face. Umm Salama went to the curtain and found the slavegirl playing. He had a siwak-stick with him and said, '"Were it not that I fear retaliation on the Day of Rising with this siwak."
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عَبْدُ اللهِ بْنُ مُحَمَّدٍ الْجُعْفِيُّ، قَالَ: حَدَّثَنَا أَبُو أُسَامَةَ قَالَ: حَدَّثَنِي دَاوُدُ بْنُ أَبِي عَبْدِ اللهِ مَوْلَى بَنِي هَاشِمٍ قَالَ: حَدَّثَنَي عَبْدُ الرَّحْمَنِ بْنُ مُحَمَّدٍ قَالَ: أَخْبَرَتْنِي جَدَّتِي، عَنْ أُمِّ سَلَمَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ فِي بَيْتِهَا، فَدَعَا وَصِيفَةً لَهُ أَوْ لَهَا فَأَبْطَأَتْ، فَاسْتَبَانَ الْغَضَبُ فِي وَجْهِهِ، فَقَامَتْ أُمُّ سَلَمَةَ إِلَى الْحِجَابِ، فَوَجَدَتِ الْوَصِيفَةَ تَلْعَبُ، وَمَعَهُ سِوَاكٌ، فَقَالَ: لَوْلاَ خَشْيَةُ الْقَوَدِ يَوْمَ الْقِيَامَةِ، لَأَوْجَعْتُكِ بِهَذَا السِّوَاكِ.
sunnah.com