To stand on the right side of the Imam on the same line if only two persons (counting the Imam) are offering Salat (prayer) in congregation

Narrated Ibn 'Abbas:

Once I passed the night in the house of my aunt Maimuna. Allah's Apostle offered the 'Isha' prayer and then came to the house and offered four Rakat an slept. Later on, he woke up and stood for the prayer and I stood on his left side. He drew me to his right and prayed five Rakat and then two. He then slept till I heard him snoring (or heard his breath sounds). Afterwards he went out for the morning prayer.

حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنِ الْحَكَمِ، قَالَ سَمِعْتُ سَعِيدَ بْنَ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ بِتُّ فِي بَيْتِ خَالَتِي مَيْمُونَةَ فَصَلَّى رَسُولُ اللَّهِ ﷺ الْعِشَاءَ، ثُمَّ جَاءَ فَصَلَّى أَرْبَعَ رَكَعَاتٍ ثُمَّ نَامَ، ثُمَّ قَامَ فَجِئْتُ فَقُمْتُ عَنْ يَسَارِهِ، فَجَعَلَنِي عَنْ يَمِينِهِ، فَصَلَّى خَمْسَ رَكَعَاتٍ، ثُمَّ صَلَّى رَكْعَتَيْنِ، ثُمَّ نَامَ حَتَّى سَمِعْتُ غَطِيطَهُ ـ أَوْ قَالَ خَطِيطَهُ ـ ثُمَّ خَرَجَ إِلَى الصَّلاَةِ.