It was narrated that 'Aishah, may Allah (SWT) be pleased with her, said: "I knocked at the door when the Messenger of Allah (ﷺ) was offering a voluntary prayer. The door was in the direction of the Qiblah so he took a few steps to his right or left and opened the door, then he went back to where he was praying."
Source: sunnah.com
Other translations
Arabic
أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا حَاتِمُ بْنُ وَرْدَانَ، قَالَ حَدَّثَنَا بُرْدُ بْنُ سِنَانَ أَبُو الْعَلاَءِ، عَنِ الزُّهْرِيِّ، عَنْ عُرْوَةَ، عَنْ عَائِشَةَ، - رضى الله عنها - قَالَتِ اسْتَفْتَحْتُ الْبَابَ وَرَسُولُ اللَّهِ صلى الله عليه وسلم يُصَلِّي تَطَوُّعًا وَالْبَابُ عَلَى الْقِبْلَةِ فَمَشَى عَنْ يَمِينِهِ أَوْ عَنْ يَسَارِهِ فَفَتَحَ الْبَابَ ثُمَّ رَجَعَ إِلَى مُصَلاَّهُ .
sunnah.com